Let f x squareroot 5x 89 and gx 3x2 1 Find f g4 Let f x

Let f (x) = squareroot 5x + 89 and g(x) = 3x^2 - 1. Find (f g)(4). Let f (x) {4x + 3, - 3

Solution

19) f(x) = sqrt (5x+89)

g(x) = 3x^2-1

(fog)(x) = sqrt {(5(3x^2-1) + 89 )}

(fog)(4 ) = sqrt (5(3(4)^2-1)+89}

(fog)(4 ) = sqrt ( 324) = 18

(fog)(4) = 18

20) for f(3) we will use the function f(x) = x-1 as <0<x<4

and x = 3 lies in this interval

therefore,

f(x) = x-1

f(3) = 3-1 = 2