Question

Given f(x)=x^2-1 and g(x)=x+1, find (fog)(x)?

Answer 1

(fog)(x) = f(g(x)) = f(x+1)

Answer 2

@shivraj u got what I did??????

Answer 3

no sir

Answer 4

that means you need to put
x= x + 1 in f(x)

Answer 5

Yep:
(fog)=f(g(x))

Answer 6

Now, substitute there g(x)

Answer 7

suppose f(1) = 0
f(x) = x^2 - 1
f[g(x)] = (x+1)^2 - 1

Answer 8

ok

Answer 9

you got it? @shivraj

Answer 10

yep

Answer 11

if \[f(x)=x^2-1\ and \ g(x)=x+1, \\ \ then \ (fog)'(x)=\ (by \ product \ rule)\ u'v+u'v, \\where\ u=f(x); \ v=g(x) \\ \therefore\ (x^2-1)(1)+(2x)(x+1)=\\x^2-1+2x^2+2x=\\3x^2+2x-1=\\(3x-1)(x+1) \]

Answer 12

thnks godfreysown