CAPE cxc

advertisement

Pedagogy for the Transition of

Mathematics Continuity

ALGEBRA

GEOMETRY

CALCULUS

PRESENTER: GLENROY PINNOCK MSc. Applied Mathematics; Marine

Engineering Diploma; Mathemusician; PhD. (EDUC)pending

JANUARY 14TH, 2011

1

What is a radical quantity in mathematics? E.g.,√a

Factor for algebraic expression:x 2 - y 2

LAWS OF INDICES

(RECALL SIX (6) OF THEM)

RADICALS

Rationalize 1

2 + √a

Factors for algebraic expressions:x 2 + y 2 , x 3 - y 3 , x 3 + y 3 , x 4 - y 4 , x 4 + y 4

2

PASCAL TRIANGLE/BINOMIAL

EXPRESSIONS

(a + b) 0

(a + b) 1

(a + b) 2

(a + b) 3

(a + b) 4

(a + b) 5

1

1 1

1 2 1

1 3 3 1

1 4 6 4 1

1 5 10 10 5 1

TOOLS FOR COEFFICIENTS IN ALGEBRAIC

EXPANSION

3

y = ax 2 + bx + c

QUADRATIC THEORY

What is the discriminant to the formula on the left? Clearly, it’s b 2 - 4ac.

The solution x = -b+√ (b 2 - 4ac)

2a

 What happens if this term is negative?

Recall that if the roots of the above quadratic equation is and β.

α

What is the sum of the roots and the product of the roots?

Write down the equation, whose roots are α 3 and β 3 ?

So, we can now discuss the significance of the discriminant.

a. The roots of a quadratic equation are imaginary/complex, if the discriminant is negative.

b. If the discriminant is greater than 0, then the roots are real.

c.

If b 2 = 4ac, then the roots are real and equal.

d. By the way, notice that these roots are basically the solutions of a quadratic equation.

PROVE THIS FORMULA!

4

TRIGONOMETRIC EQUATIONS

sine θ = 0.5

Clearly sine θ = ½

Do you remember trig-ratios?

Do you recall the quadrant system?

What does that equation mean for the positive 0.5?

What happens if 0.5 is negative?

Solve:sine 2θ = 0.5, sine 3θ = 0.5

WOW!

What is the difference for the number of solutions, for the equations above?

Solve: sine 2 2θ = 0.25

We are ultimately breaking down

2 nd degree trig equations into a 1 st degree equation or factor.

5

THE POLYNOMIAL [P(x)]

2

4 9

- 8

1

This can be written as

9 = 2 (4) + 1.

Conceptually, we can say 9 represents a polynomial, 2 is the quotient, 4 is the divisor, and 1 is the remainder.

Let us now divide x 2 – 1 by x + 1.

Clearly, x 2 – 1≡ Q (x + 1) + 0.

How did I get a zero?

So, generally speaking

P (x) ≡ Q (x + a) + R.

NB: It is advisable to represent a remainder theorem/factor theorem problem in this format.

Remember to use the synthetic rule to reduce tedious long division. Also, you need to know how to solve a pair of simultaneous equations.

6

LOGARITHMS

Always recall the laws of indices and indicial equations whenever you are doing log problems.

What is the logarithm of a number?

Now consider log

10

10 = ?

10 1 = 10

Similarly, log e

100 = y.

Clearly, e y = 100.

Now we can say it’s the definition of a logarithmic quantity.

7

GEOMETRY

What is the difference between a horizontal line & a slanted line?

Let’s consider the slanted line:

B (x

1

, y

1

)

A (x

2

, y

2

)

What is the gradient of AB?

Clearly, grad AB = y

1 x

1

- y

- x

2

2

 Two parallel lines will have equalgradients.

 When one line is perpendicular to another, the product of their gradients is -1.

Consider the points A(2, 3) and

B(-1, -2). What is the equation of the line?

Recall y = mx + c

*c is the y intercept and m is the gradient.

Also, the gradient of a straight line is also equal to the tangent of inclination (tanθ) of the slanted line.

8

h

GEOMETRY

(CONT’D)

area of a right-angled triangle

Construct a parallelogram from the points given above, and also find the area of the figure. Prove that the parallel sides of the parallelogram have equal gradients.

A = ½ bh

Construct a rhombus with points of your choice, and find the area of the rhombus.

Prove that the diagonal of the rhombus intersects at 90 0 .

b

Area of a non-right angled triangle

A= ½ ab sin C

This equation also can be written in two other forms. What are these forms?

NB: The coordinates for the point of intersection of two lines is basically the solution of two simultaneous equations.

9

STATISTICS

 the multiplication law and the addition law

 cumulativefrequency curve (OGIVE)

 upper quartile, lower quartile, median, inter-quartile range, semiinter quartile range

 percentiles

 frequency polygon

 permutation & combination

 probability distribution

 Poisson distribution

 binomial distribution

 orientation of the sample space diagram

 normal distribution

10

CALCULUS

Recall gradient (grad) of a straight line:

AB = y x

1

1

-y

-x

2

2

Remember that this represents a straight line.

Concept of a limiting value.

In the case of a curve, the gradient is found by considering the differential expression, namely, dy , f

׳

, f x dx

0

So, what is your interpretation of the limiting value?

δ y

δ y

δ x

δ x

As a novice, we can say dy ≡ δ y dx δ x

As δ x 0 that is the time dy = δ y dx δ x

11

CALCULUS

(CONT’D.)

DISCUSSION

 differentiation by first principles

 differentiation of a product

 differentiation of a quotient

 differentiation of trigonometrical expressions

 implicit differentiation

 differentiation by approximation

 differentiation express by rate of change

Clearly dy represents the gradient dx which is the tangent of the angle of inclination.

Differentiation by formula y = x n

dy

= nx n-1

dx

Finally, to differentiate means to find dy from y.

dx

Differentiate this equation: y = x 3 – x -2 + x 4

12

INTEGRATION

B

A

The area under the line AB is ?

B

A

However, the area under the curved AB is found by integration.

Let us consider this curve to be y = x 2 for x ≥ 0.

The area under the curve is ydx.

On the other hand, the volume under the curve is y 2 dx, if the revolution is done about the x axis through 360 0

What would be the formula for the volume of revolution about the y axis?

13

INTEGRATION

Integration is considered to be anti-differentiation

(anti-derivative)

Given that y = x 2 dy= 2x dx

So, the integral of 2x can be written as 2x

By considering the formula dy= x n dx

∴ y = x n+1 n + 1

Clearly, 2x .dx = x 2

Finally, we can now say integration is to find y whenever dy dx

14

INTEGRATION

(CONT’D.)

DISCUSSION

 Integration of a binomial expression to the n power

 Integration of a trigonometric function

 Integration by parts

IN A NUTSHELL THE INTEGRAL SYMBOL REPRESENTS SIGMA

NOTATION IN INTEGRATION THEORY.

Glenroy ‘Ajaniah’ Pinnock

15

Download