SOLUTION: find (gof)(x) f(x)=/2x/ and g(x)=-5x I came up with -5x+/2x/ but I'm just not sure. thanks Lee Ann

Algebra ->  Rational-functions -> SOLUTION: find (gof)(x) f(x)=/2x/ and g(x)=-5x I came up with -5x+/2x/ but I'm just not sure. thanks Lee Ann      Log On


   

Question 29850: find (gof)(x)
f(x)=/2x/ and g(x)=-5x
I came up with -5x+/2x/ but I'm just not sure.
thanks
Lee Ann
Answer by sdmmadam@yahoo.com(530) About Me  (Show Source):
You can put this solution on YOUR website!
find (gof)(x)
f(x)=/2x/ and g(x)=-5x
f(x)=/2x/ ----(1) and g(x)=-5x----(2)

f(x)=/2x/ =+(2x) if x>=0
f(x)=-(2x) if x<0
That is to say whether x>0 or <0 , f(x) is always positive for x NOT ZERO and let this positive quantity be t and for x=0,we have t=0 of course.
Now (gof)(x) = g(f(x)) = g(|2x|)(using (1))
=g(t)= -5t (using (2))
=-5X(2x) where 2x is positive
That is (gof(x)) =-10x which is a negative quantiy