10 20 30 40 50 60 A man drops a ball from the top of a building. After ½ second, the ball has fallen 4 feet. 10 1/2 20 30 40 50 60 4 After 1 second, the ball has fallen 16 feet. 10 10 1/2 20 20 30 30 40 40 50 50 60 60 1 4 16 After 3/2 second, the ball has fallen 36 feet. 10 10 10 1/2 20 20 20 30 30 30 40 40 40 1 4 16 3/2 36 50 50 50 60 60 60 After 2 seconds, the ball has fallen 64 feet. 10 10 10 10 1/2 20 20 20 20 30 30 30 30 40 40 40 40 1 4 16 3/2 36 50 50 50 50 60 60 60 60 2 64 Motion is described as a set of ordered pairs. 10 20 30 { ( 1/2 , 4 ), ( 1 ,16 ), ( 3/2 , 36 ), ( 2 , 64 ) } 1/2 1 4 16 40 3/2 36 50 60 2 64 Motion is described as a set of ordered pairs. 10 20 30 { ( 1/2 , 4 ), ( 1 ,16 ), ( 3/2 , 36 ), ( 2 , 64 ) } Sometimes there is a pattern, and we can write an equation: 1/2 1 4 16 40 d = 16 t2 3/2 36 50 60 t is time in seconds d is distance in feet 2 64 More generally, a function is defined as a set of ordered pairs. 10 20 30 { ( 1/2 , 4 ), ( 1 ,16 ), ( 3/2 , 36 ), ( 2 , 64 ) } When we write an equation for a function, the solutions (ordered pairs) define the function. 1/2 1 4 16 40 d = 16 t2 3/2 36 50 60 t is time in seconds d is distance in feet 2 64 A function is defined as a set of ordered pairs. 10 20 30 40 { ( 1/2 , 4 ), ( 1 ,16 ), ( 3/2 , 36 ), ( 2 , 64 ) } The DOMAIN of the function = { 1/2 , 1 , 3/2 , 2 } The RANGE of the function = { 4 ,16 , 36 , 64 } 1/2 1 4 16 3/2 36 50 60 2 64 10 20 30 The DOMAIN of the function = 1/2 1 3/2 2 The RANGE of the function = 4 16 36 64 The function is a mapping that relates every Domain element t to a unique corresponding Range element, denoted f(t) and called the image of t 1/2 1 4 16 40 3/2 36 50 60 2 64 10 20 30 The DOMAIN of the function = 1/2 1 3/2 2 The RANGE of the function = 4 16 36 64 The function is a mapping that relates every Domain element t to a unique corresponding Range element, denoted f(t) and called the image of t 1/2 1 4 16 40 50 60 4 is the image of ½ 16 is the image of 1 36 is the image of 3/2 64 is the image of 2 4=f(½) 16 = f ( 1 ) 36 = f ( 3/2 ) 64 = f ( 2 ) 3/2 36 2 64 10 20 30 40 50 60 The DOMAIN of the function = 1/2 1 3/2 2 The RANGE of the function = 4 16 36 64 The function (of high school algebra fame) relates a set of real numbers to another set of real numbers. 1/2 1 4 16 Next we will examine a mapping that links a set of vectors to another set of vectors. In doing 3/2 36 so, we use much of the same terminology that we used in the study of functions. A function is a type of mapping. 2 64 A farmer plans to purchase a herd of cows. He considers 2 breeds: Purple cows and Brown cows Each day a purple cow will eat 1 bale of hay and will produce 2 bottles of milk Each day a brown cow will eat 2 bales of hay and will produce 3 bottles of milk purple brown 50 70 190 310 A herd comprised of 50 purple and 70 brown cows will consume 190 bales of hay and produce 310 bottles of milk. 50 70 190 310 purple brown 50 70 100 30 190 310 160 290 A herd comprised of 100 purple and 30 brown cows will consume 160 bales of hay and produce 290 bottles of milk. 100 30 160 290 purple brown 50 70 100 30 80 150 190 310 160 290 380 610 A herd comprised of 80 purple and 150 brown cows will consume 380 bales of hay and produce 610 bottles of milk. 80 150 380 610 purple brown 50 70 100 30 80 150 The DOMAIN of the mapping: These vectors describe the composition of the herd, and this determines 190 310 160 290 380 610 purple brown 50 70 100 30 80 150 The DOMAIN of the mapping: These vectors describe the composition of the herd, and this determines 190 310 160 290 380 610 The RANGE of the mapping: These vectors describe the daily food intake and milk yield. purple brown 50 70 100 30 80 150 190 310 160 290 380 610 Just as it is sometimes possible to find an equation to define a function, it is sometimes possible to produce a matrix to define a vector space mapping. purple brown 50 70 100 30 80 150 190 310 160 290 380 610 Just as it is sometimes possible to find an equation to define a function, it is sometimes possible to produce a matrix to define a vector space mapping. # bales of hay = 1 (# purple cows) + 2 (# brown cows) purple brown 50 70 100 30 80 150 190 310 160 290 380 610 Just as it is sometimes possible to find an equation to define a function, it is sometimes possible to produce a matrix to define a vector space mapping. # bales of hay = 1 (# purple cows) + 2 (# brown cows) # bottles of milk = 2 (# purple cows) + 3 (# brown cows) purple brown 50 70 100 30 80 150 190 310 160 290 380 610 Just as it is sometimes possible to find an equation to define a function, it is sometimes possible to produce a matrix to define a vector space mapping. # bales of hay = 1 (# purple cows) + 2 (# brown cows) # bottles of milk = 2 (# purple cows) + 3 (# brown cows) # bales 1 2 # purple # bottles 2 3 # brown purple brown 50 70 100 30 80 150 eg: 190 310 160 290 380 610 # bales 1 2 100 # bottles 2 3 30 # bales 1 2 # purple # bottles 2 3 # brown purple brown 50 70 100 30 80 150 eg: 190 310 160 290 380 610 160 1 2 100 290 2 3 30 100 , to find the vector related to 30 100 1 2 by multiply 30 2 3 # bales 1 2 # purple # bottles 2 3 # brown purple brown 50 70 100 30 80 150 190 310 160 290 380 610 For every domain element v ( a vector in R2 whose entries are the numbers of each breed of cow) there is a unique corresponding range element Av ( a vector in R2 whose entries are the numbers of bales consumed and bottles produced.) A # bales 1 2 # purple # bottles 2 3 # brown purple brown 50 70 100 30 80 150 190 310 160 290 380 610 eg: 100 1 2 100 160 100 the image of A 30 2 3 30 290 30 A # bales 1 2 # purple # bottles 2 3 # brown