math
posted by Jeromino .
f(x)= 3x5 and g(x)= 2x^2 evaluate:
1.(fog)(x)
2.(gog)(2)

(fog)(x) means you substitute the whole function of g(x) into the f(x),, we can actually rewrite this (fog)(x) as f(g(x))  i think this one is clearer.
now let's substitute g(x) to f(x):
(fog)(x) = f(g(x)) = 3x5 = 3[g(x)]  5
(fog)(x) = 3(2  x^2)  5
(fog)(x) = 6  3x^2  5
(fog)(x) = 3x^2 + 1
for #2, we do the same,, we substitute g(x) to g(x) then we evaluate the simplified expression at x=2:
(gog)(x) = g(g(x)) = 2  (g(x))^2
(gog)(x) = 2  (2  x^2)^2
(gog)(2) = 2  [2  (2)^2]^2
(gog)(2) = 2  [2  4]^2
(gog)(2) = 2  (2)^2
(gog)(2) = 2  4
(gog)(2) = 2
hope this helps~ :) 
Thanks a bunch

Yes thank you very much!
Respond to this Question
Similar Questions

Calculus
Hi there, I need help with composition of functions. I need to find fog, gof, gog, and fof and their domains for the following: f(x) = square root of 2x +3 g(x) = x^2 + 1 if someone can help me asap that would be so great! 
math
Solve the two sided inequality and show the solution on real line 7 < 12x ≤ 10 Given two functions as: f(x) = and g(x) = Find fog(x) also find the domain of f, g and fog Simplify, then apply the rules of limit to evaluate 
Composite Functions
f(x)=(7x+28)/(x3) and g(x)=(3x+28)/(x7) Find: (fog)(x) (gof)(x) (fog)(1) 
math
Find a. fog b. gof c. fof d. gog f(x)=4x g(x)=3x5 
math
Find a. fog b. gof c. fof d. gog for each function f(x)=4x g(x)=3x5 
math
find the domain of the composite function fog. f(x)=x/x2;g(x)=8/x a. domain of fog is {x/? 
Math. Need help
1.if g=5 and k=1, evaluate 9+gk a. 13 b. 14 c. 15 d. 16 2.Evaluate ab^2/b if a = 10 and b = 2. a. 1 b. 3 c. 8 d. 32 3.Evaluate 3xy^2  y if x = 2 and y = 5. a. 26 b. 30 c. 120 d. 145 4.Evaluate 2d + d^2/3 if d = 6. a. 4 b. 12 c. 14 … 
maths
f(x)=x^2+3x+1,g(x)=2x3, find fog and gog 
Algebra
What is the value of (fog)(5) f(x)=x10 ; g(x)=x23 a. (fog)(5)= 38 b. (fog)(5)=12 < ? 
ELA
The following line from the poem represents which central idea?