Question

f(x) = 1/(1+x) then what is f(1/x)=? is it f(1/x)= x+1 ? in text it says f(1/x)=x/(1+x) why?

Answer 1

plug the value of 1/x instead of x to get your answer??

Answer 2

and you are correct, maybe the book has made a error???

Answer 3

this was in spivak's book the answer I found in the solution manual but I didn't get the logic

Answer 4

Book is right

Answer 5

I know that Spivak can't be wrong but what is the logic?

Answer 6

Same as Sarkar said

Answer 7

f(x) means the function will only contain values of x
f(1/x) means all the x values will be substituted by 1/x

Answer 8

So we get the answer as x/(1+x)

Answer 9

yes @shabeer

Answer 10

provided x is not equal to -1 & 0 , isn't?