REMEMBER!!!! • Have a quick look at the paper first, making small notes if necessary, then answer what you know you can do first. • Always attempt EVERY question no matter what, showing as much working as possible. • Remember to use the formulae sheet provided, and if unsure of a question look at this, as it may trigger something in your mind. • Check all of your answers if you have time at the end. Formulae to Remember:The Formulae NOT given in exam which you must know include: To calculate the Area of a Sector Area of a circle: A = r2 To find Arc Length Circumference: C = D = 2r Inter Quartile Range (measure main 50% spread in Boxplots): IQR = Q3 – Q1 Semi-Inter Quartile Range SIQR = 1/2(Q3 - Q1) Standard Form/Scientific Notation (a x 10n) The final value must be between 1 and 10 [i.e. 99 x 104 must be written as 9.9 x 105] 4230000 = 4.23 x 106 13280000 = 1.328 x 107 0.000975 = 9.75 x 10-4 2 million million = 2 x 1012 1.2 x 103 = 1200 2.91 x 10-2 = 0.0291 7.425 x 106 = 7425000 5.23 x 10-5= 0.0000523 More complex calculations • A massive container holds 4.23 x 106 litres • A spoon holds 1.52 x 10-2 litres Question:- How many spoonfuls fill the container? give your answer to 3 sf & in standard form Answer:- (use EXP button on calculator for ease) 4.23 x 106 = (4.23 EXP6) = 278289473.684 =2.78 x 108 1.52 x 10-2 (1.52 EXP-2) spoonfuls Significant Figures Round the figure to a certain number of important or significant digits. It is NOT rounding to a certain amount of decimal places. E.g. If you have to represent 2323 to 1sf you would write 2000 (NOT 2). As the original number is in thousands, your rounded figure should still be in thousands. 14243 to 1sf is 10000 16.932 to 1 sf is 20 14243 to 2sf is 14000 16.932 to 2 sf is 17 14243 to 3sf is 14200 16.932 to 3 sf is 16.9 1.2374 to 1 sf is 1 1.2374 to 2 sf is 1.2 1.2374 to 3 sf is 1.24 0.00237 to 1 sf is 0.002 0.00237 to 2 sf is 0.0024 0.00237 to 3 sf is 0.00237 • NB In the last example zeros are not significant at the front of a number, the first significant digit must be one or more. Conversion: • Remember to pay attention to the units required and to how many dec plcs/sig figs! • 60mins 1 hr • to convert into hours we must therefore 60 (secs to mins 60) (SDT!!!) • 1cm3 = 1ml & 1000cm3 = 1000ml = 1litre • 1m3 = 1m x 1m x 1m = 100cm x 100cm x 100cm = 1,000,000cm3 Fractions ADDING/SUBTRACTING:- the denominator must be the same e.g. 2 + 5 = 2(y-1) + 5y = 2y-2 + 5y – 5 = 7y – 2 y (y-1) y(y-1) y(y-1) y(y-1) MULTIPLICATION:- Multiply straight over and then simplify e.g. a x 2b = 2ab = b 4c a 4ac 2c DIVISION:- Change to multiply turn fraction upside down e.g. ab a = ab x 3c = 3abc = b 9c 3c 9c a 9ac 3 • • Substitution **Remember (-3)2= 9 NOT –9 and follow rules of BODMAS! BODMAS Brackets Order Divide Multiply Add then Subtract Algebraic Fractions • Remember to follow through from previous part of factorising question if given an algebraic fraction, then simplify wherever possible: x2 – 8x + 7 = (x – 7) (x – 1) = (x – 1) x 2 - 49 (x – 7) (x + 7) (x + 7) Profit/Loss (Appreciation/Depreciation) can be calculated as a percentage by:- Difference in Value x 100% = % Profit or Loss Original Value To make into a percentage. Given 12 out of 30 pupils are girls, what is this as a percentage of all pupils? 12 out of 30 can be written as 12 = 4 = 40 30 10 100 {NB easier to make into a percent if over 10 or 100} Compound Interest Shortcut Method [£ x (1.00 + %)y] Appreciation:- The value increases by itself (100%) + the % increase e.g 5% increase in value is (100% + 5%) = 105% so multiplying factor 1.05 Depreciation:- The entire value decreases (100%) - % decrease e.g 5% decrease in value is (100% - 5%) = 95% so multiplying factor 0.95 Example of Compound Interest Ex: Calculate compound interest when investing £720 at a rate of 5.7% over 3 years? An increase in 5.7% over 3 years can be written as (1.00 + 0.057)3 (1.057) 3 £720 x (1.057) 3 = £850.27 (to the nearest penny) [Only use this method if same percent change each year.] Reversing Values (i.e. Going Backwards to find original value** DIFFICULT) After a 10% increase a house is worth £88 000. Find its original value? Original value = 100% House is now valued at (100% + 10%) = 110% = 1.10 House Value 110% £88 000 1.10 £88 000 1 £88 000 = £80 000 1.10 A car depreciates in value by 12% over the year and is now £9680. What was its value at the start of the year? Original value = 100% Car is now valued at (100% - 12%) = 88% = 0.88 Original Car Value 88% £9 680 0.88 £9 680 1 £9 680 = £11 000 0.88 Circles 1 Arc Length is part of the circumference, so use A x D 360 2 Area of a Sector is related to ‘Area’, so use A x r2 360 3 In the circle a line, or tangent, to the circle creates an angle of 90o 4 Any triangle in a semi-circle with an angle touching the circle has an angle of 90o 5 Use radii, right angled triangles and Pythagoras theorem when given ‘Chords’ in a circle. 1&2 3 4 5 r A Chords • Always use the radius in this question to create a right angled triangle. • Using Pythagoras or basic trig you may then find the unknown side • If finding the height of a tunnel take unknown + radius • If finding depth below take radius - unknown Make into a right angled triangle • Bottom depth will be H = (radius – x) • Height will be H = (radius + x) • If to find radius need to use pythagoras & solve algebraically as a Quadratic problem x r x r r r (r-x) x r Make into a right angled triangle A x x A r B 5cm 4cm 8cm B • Given AB = 8cm and r = 5cm find the depth of water below chord AB? • x2 = r2 – (OB)2 x2 = 52 – 42 = 25 – 16 =9 x = √9 = 3cm Depth below AB: D = (radius – x) = 5cm - 3cm = 2cm depth Make into a right angled triangle C x D r r • x2 = r2 – (OD)2 x2 = 102 – 62 6cm = 100 – 36 D 10cm = 64 x = √64 = 8cm r 12cm C x 10 • Given CD = 12cm and r = 10cm • Find the water level Height at CD? Water level at CD : H = (radius + x) = 10cm + 8cm = 18cm high Make into a right angled triangle E x F r r 12cm 3 6cm E (r - 3) r cm F • Given EF = 12cm and x = 3cm • Find the radius, r? • r2 = (r - 3)2 + 62 r2 = r2 – 6r + 9 + 36 6r = 45 r = 45 = 7.5cm 6 Linear Relationships : y = mx + c Line cuts Y-axis at (0,c) thus can find value of ‘c’ by looking at graph Gradient is ‘m’ which can be found by Gradient m = Vertical = Rise = Difference in y’s = y2 - y1 Horizontal Run Difference in x’s x2 – x1 If asked to draw a line given an equation: • Make a small grid with x values 0, 1, 2 and plot line i.e. if y = 3x - 4 Y = 3x – 4 • x 0 1 2 y -4 -1 2 thus can plot 3 coords (0, -4); (1, -1) & (2, 2) and extend to draw a line • Special Cases:Gradient = 0 Gradient Undefined Remember Positive Gradients Uphill (Positive) Negative Gradients Downhill (Negative) & Parallel lines have the same gradient Algebra: Opening Brackets • Always use a FOIL to help multiply two brackets (x + 2)(x + 6) = x2 + 2x + 6x + 12 = x2 + 8x + 12 (x - 4) 2= (x -4)(x - 4) = x2 - 4x - 4x + 16 = x2 - 8x + 16 If a larger bracket is to be opened then it may be easier to use a grid:(x + 5)( x2 + 8x + 12) = x3 + 8x2 + 5x2 + 12x + 40x + 60 = x3 +13x2 + 52x + 60 x2 + 8x + 12 x x3 + 8x2 + 12x +5 5x2 + 40x + 60 x3 + 13x2 + 52x + 60 Understanding the signs x2 + 5x + 4 = (x + ?)(x + ? ) = (x + 1)(x + 4) All signs positive so either 1 x 4 or 2 x 2 to get 4 at end. As 5 in middle => must use 1 and 4 x2 – 14x + 13 = (x - 1)(x - 13) 13 is positive, BUT -14x in middle => 2 negatives multiplied together to get +13 Prime number so can only be -1 x -13 which gives -14 in middle x2 + 2x – 3 = (x + 3)(x - 1) -3 implies must be 2 different signs + / - to give -3 -3 x 1 or 3 x 1. As +2x in middle must be 3 and -1 x2 – 6x – 7 = (x - 7)(x + 1) -7 implies 2 different signs to make -7 => Either -7 x 1 or +7 x -1 As -6x in middle the larger number is influencing a negative result Thus -7 and 1 shall give -6x in middle Summary x2 + ?x + ? => Both + & sum gives positive middle value x2 – ?x + ? => Both – & sum gives negative middle value x2 + ?x – ? => 2 different signs & difference gives positive middle value (Large part is Positive) => 2 different signs & difference gives negative middle value (Largest part is Negative) x2 – ?x – ? ALWAYS FOLLOW THE SAME PROCEDURE EACH TIME WHEN FACTORISING:Is there a COMMON FACTOR? i.e. 2x - 12x = 2x(x – 6) Is there a DIFFERENCE OF TWO SQUARES? 4a – 25b2 = (2a) – (5b) = (2a + 5b)(2a – 5b) Can it FACTORISE (Is it a trinomial in 3 parts?) x – 8x + 7 = (x – 7)(x – 1) ELSE if to solve to A SPECIFIC NUMBER OF DECIMAL PLACES OR SIGNIFICANT FIGURES use the QUADRATIC FORMULA Solving a Quadratic Problem Example: Solve the following x2 – 8x + 7 for x x2 – 8x + 7 = 0 (Set = 0 if not given) (x – 7)(x – 1) = 0 (Factorise quadratic) (x – 7) = 0 & (x – 1) = 0 x=7 & x=1 Quadratic Formulae Use when factorisation is not possible and asked to a specific number of decimal places/significant figures ax2 + bx + c = 0 and a 0 where a, b and c are constants from the quadratic x = -b +/- (b2 - 4ac) 2a (******* formula given on worksheet ********) Sketch the graph of f(x) = (x - 4) 2 - 1 1. 2. 3. 4. 5. Positive 'a' Happy U Minimum Tpt Vertex (b,c) Minimum Tpt at (4, -1) Symmetry at x = 4 Cuts y-axis at x=0, y = (0 - 4)2 - 1 = (16) - 1= 15 So cuts at (0,15) Cuts x-axis at y=0, (x - 4) 2 - 1 = 0 x2 – 8x + 16 – 1 = 0 x2 – 8x + 15 = 0 (x – 3)(x – 5) = 0 x–3=0&x–5=0 x=3 & x=5 So cuts at (3, 0) & (5, 0) Having obtained all information it is then possible to sketch the quadratic graph. Volume of Solids Volume of a Cone : V = 1r2h 3 [Easier to multiply values Volume of a Sphere: V = 4r3 3 together and by 3 at the end] *** 2 Formulae NOT Given to you Vol of a Cylinder: V = r2h & Vol of ANY Prism : V = Ah (Main shape x height) **** Make sure answer to the correct number of decimal **** places OR significant figures, else marks will be lost! Simultaneous Linear Equations : 3 Methods • 1. Graphical: This solves for the values of x and y where both lines have same value (i.e. they cross/intersect). It is necessary to sketch two lines for this and the point of intersection is the where the solution can be found. • 2. Substitution: Place one equation into the other and solve using substitution. e.g y = 2x and y = -x + 12 y =3x and 7x + 2y = 39 If y = y using the method of substitution 2x = -x + 12 2x + x = 12 3x = 12 x=4 This time subst y = 3x into other equation 7x + 2y = 39 7x + 2(3x) = 39 7x + 6x = 3 13x = 39 x=3 Then find y using either equation given at start. Simultaneous Linear Equations 3. Elimination: Whenever presented with TWO EQUATIONS and you need to find the values of x and y, p and q etc Use the system of SIMULTANEOUS EQUATIONS • ALWAYS eliminating one variable to solve for one, then substitute this into the equation to find the other. • SAME SIGNS => SUBTRACT EQUATIONS • DIFFERENT SIGNS => ADD EQUATIONS TOGETHER • Then use this value to find the other unknown choosing ANY equation. Statistics • You must know how to interpret, construct and present the following:• Bar and Line graphs • Stem and Leaf Plot and Pie charts • Frequency tables, diagrams and polygons • Cumulative Frequency diagrams • Box Plots; Dot Plots and 5-Figure Summary • Probability and Relative Frequency (same idea as probability) • Scatter Diagram • Standard Deviation Boxplots • 1. 2. 3. 4. 5. You must ORDER DATA & find the 5-figure Summary:L or Min - minimum value Q1 - 1st/lower quartile Q2 - median (or middle value) Q3 - upper/3rd quartile H or Max - maximum value NOT given in the exam so MUST be remembered! To find the spread of the main 50% of your information use:• The IQR (Inter Quartile Range) = (Q3 - Q1) • SIR (semi-inter quartile range) is SIQR =1/2(Q3 - Q1) Stem and Leaf Plots Remember to put a key for the data • Draw a vertical line with the main number group being the ‘stem’, and the remaining smaller units of the number being the ‘leaves’. • Place in numerical order from the lowest to highest value and represent every piece of data, even if a number is repeated more than once. Dot Plots • Draw a horizontal scale from the lowest to highest value • Horizontal scale must be in numerical order. • Represent each piece of data above the scale with a dot • If repeated values place a dot above the previous data value entered. Scatter Diagrams Refer to “GCSE Maths Revision book” this is a good example to follow. Ensure line going through data cuts y-axis to find y intercept, c. Try to have same amount of data above & below line, and about same distance from line. Standard Deviation: Method 1 • Create a table with 3 columns with the following headings: _ _ x (x – x) (x – x)2 x • & mean of x being _ (x - x) _ (x - x)2 _ x bar, x = x n Standard Deviation: Method 2 • Create a table with 2 columns with the following headings: x2 x x x2 • (∑ means the total sum of) • NB:- If presented with Standard Deviation data in the format • x2 = 12345 and x = 123 use the 2nd formula given on the front sheet without creating a table. Similar Shapes • Similar triangles are Equiangular have the same angles & sides are in proportion Scale Factor (SF) • Similar Areas. Area units are cm2 (Scale Factor) 2 • Similar volumes have all dimensions in proportion i.e Volume units are cm3 (Scale Factor) 3 Separate Similar Triangles • When can’t see the problem clearly make a new sketch by separating the triangles. • This will make the problem far more clear. Redraw complicated shapes • Use z-shape angle rules & separate for simplicity A α θ * C * B C B θ * C * θ D α θ E D α α E A Ratio and Proportion Ratio If Michael, Lisa and Stephanie share a bag of 81 sweets in the ratio 2:3:4, how many sweets does each person get? • Add parts together to find total amount of shares 2+3+4=9 • Take value and divide by total shares to find 1 share 81 9 = 9 • When you have found 1 share 9 sweets here, you can then substitute back into original ratio 2 : 3 : 4 2x9:3x9:4x9 18 : 27 : 36 • Check by adding together 18 + 27 + 36 = 81 sweets Problem Solving with Sequences If given a sequence e.g. 3, 7, 11, 15,… find the formula for the sequence: E.g. nth term 1 2 3 4 5 …. N Sequence 3 7 11 15 19 … 4N – 1 +4 +4…. +4 (4*N ; As increases by 4 each time) Variation Direct Variation When both increase/decrease at same rate i.e. as one halves the other halves y = kx or y x Inverse As x increases y decreases i.e.Time for job to be completed reduces as manpower increases. y = k or y 1 x x Surds 3 x 3 = 9 =3 2 x 50 = 100 = 10 12 3 = 4 =2 72 = 36 x 2 = 62 72 + 50 - 98 = (36 x 2) + (25 x 2) – (49 x 2) = 62 + 52 – 72 = 42 • Can multiply/divide straight away • You can only add/subtract if a ‘common surd’ exists . • Remember Rationalise Do not leave as surd on denominator Surds Simplify and RATIONALISE: 5 3 + 1 = (5 3 + 1) x (4 3 – 7) (43 + 7) (43 + 7) (43 - 7) = 2033 -35 3 + 43 – 7 1633 -283 + 283 – 49 Find the area of the rectangle: (3 + 1) (23 – 5) = (3 x 2 3) - 53 + 2 3 - 5 = 2 x 3 – 5 - 3 3 = 1- 3 3 (23 – 5) = 20x3 - 313 - 7 16x3 – 49 = 60 – 7 - 313 48 – 49 = 313 – 53 -1 = 53 - 313 (3 + 1) Indices ax ay = ax-y a7 a4 = a3 a5/2 a1/2 = a4/2 = a2 ax x ay = a x+y a 2 x a3 = a 5 a3/2 x a5/2 = a8/2 = a4 a x/y = yax 82/3 = 3 (82)= 364 = 4 or 82/3 = (38)2 = 22 = 4 a0 = 1 and a-1 = 1 a • Easy to remember that a ‘x’ sign is a slanted ‘+’ sign so if multiplying weADD the powers • If ‘’ or ‘/’ think of ‘-‘ within symbol i.e. when dividing indices we SUBTRACT the powers Indices b1/2( b1/2 + b-3/2) = (b1/2 x b1/2) + (b1/2 x b-3/2) = b1/2+1/2 + b1/2 - 3/2 = b2/2 + b-2/2 = b + b-1 or b + 1 b y7 x y-4 y3 a-4/5 x a-3/5 a-2/5 = y3 y3 = a-7/5 a-2/5 = y3-3 = a-7/5 –(-2/5) = y0 = a-7/5+2/5 =1 = a-5/5 = a-1 or 1 a Right Angled Triangles • SOH CAH TOA and Pythagoras only in Right Angled Triangles. • Pythagoras if sides only c2 = a2 + b2 • If angles and sides use SOH CAH TOA Sin x = O; Cos x = A; Tan x = O H H A Sine Rule If NOT RIGHT ANGLED must consider other trig rules When related angle and side present (i.e. you can draw a diagonal between side and angle) Use the Sine Rule To find a side: Reverse Sine Rule To find an angle: a = b = c Sin A Sin B Sin C Sin A = Sin B = Sin C a b c Cosine Rule When two sides and unrelated angle use Cosine Rule a2 = b2 + c2 –2bc CosA Or when 3 sides and no angle use Cosine Rule CosA = b2 + c2 – a2 2bc Area of Triangle A = 1abSinC 2 Bearing Questions • Extend North lines to create Z-shapes to find as many angles as possible: If trig question asks to find HEIGHT and you do not have enough info to do this • Remember to firstly find the slope using sine rule or cosine rule • Then use basic SOH CAH TOA B B a? A b H a C A b Sketch 2 separate triangles • Remember to firstly find the slope using sine rule or cosine rule • Then use basic SOH CAH TOA Z Z w h? Y Z h x? W X W X Y x Trigonometric Graphs Y = aSin(bx) + c & Y = aCos(bx) + c a AMPLITUDE in front of function gives the height of the graph. If unsure take the lowest to highest values and half to get height b REPETITIONS is found within the function beside x. [i.e. how many times it is repeated in 360o] c moves the graph up/down the y-axis Max = (c + a ) & Min = (c – a) which tell us the Max/Min heights The value of b also changes the PERIOD of the curve (360/b) Period = 360/b [The number of degrees for a complete wave] Trigonometric Equations 1. 2. 3. 4. Re-arrange equation to get trig function by itself Use inverse function to find the 1st Quadrant angle Select the appropriate Quadrants from the grid below Apply the appropriate rule to find the angles (180 – x) SIN (180 + x) TAN ALL x COS (360 – x) Maximum Difference • If the depth in metres, D, of water in the harbour at time t is represented by the equation: D = 11.3 + 5.7cos (50t) • Find the MAXIMUM DIFFERENCE???????? • MAX D = 11.3 + 5.7 =17.0 • MIN D = 11.3 – 5.7 = 5.6 • THE MAX DIFFERENCE :- 17.0 – 5.6 = 11.4 metres Things to remember 1. You can write with a pencil BUT you are asked to write in pen 2. Make sure you bring your calculator and a ruler 3. Calculator cases must be left outside exam 4. Get me to check your calculator screen in the morning in case it is in the wrong mode Things to remember 5. BRING IN YOUR TEXT BOOKS, PAST PAPERS, AND ALL SCHOOL BOOKS ON DAY OF EXAM OR AS SOON AS POSSIBLE AFTER THE EXAM!!! 6. THE NEW 4TH YEAR NEED THEM TO START THEIR COURSE EVEN IF YOU AREN’T STARTING 5TH YEAR YET!! AND MOST OF ALL.. • ENJOY YOUR EXAM AND TRY YOUR HARDEST…. • You have all the keys and skills to do well, so go for it and enjoy yourself REMEMBER!!!! • Have a quick look at the paper first, making small notes if necessary, then answer what you know you can do first. • Always attempt EVERY question no matter what, showing as much working as possible. • Remember to use the formulae sheet provided, and if unsure of a question look at this, as it may trigger something in your mind. • Check all of your answers if you have time at the end.