# Function composition

• Nov 17th 2006, 03:29 AM
Function composition
Given $\displaystyle f(x) = \frac{3}{x}$

Is it gonna be $\displaystyle f(x+h) = \frac{3}{x} + h$
or
$\displaystyle f(x+h)=\frac{3}{x+h}$

another question
Given $\displaystyle G(x) = \sqrt{4-x}$

is it gonna be $\displaystyle G(x+h) = \sqrt{4-x+h}$ or $\displaystyle \sqrt{4-x} + h?$
• Nov 17th 2006, 03:36 AM
malaygoel
Quote:

Given $\displaystyle f(x) = \frac{3}{x}$

Is it gonna be $\displaystyle f(x+h) = \frac{3}{x} + h$
or
$\displaystyle f(x+h)=\frac{3}{x+h}$

another question
Given $\displaystyle G(x) = \sqrt{4-x}$

is it gonna be $\displaystyle G(x+h) = \sqrt{4-x+h}$ or $\displaystyle \sqrt{4-x} + h?$

in the first question,
you are replacing x by x+h in left hand side......... so what would be the change in right hand side, x would be replaced by x+h, hence your second attempt is correct..

Think about the second question the same way
Keep Smiling
Malay
• Nov 17th 2006, 03:55 AM
$\displaystyle G(x) = \sqrt{4-x+h}$or$\displaystyle \sqrt{4-(x+h)}?$
$\displaystyle G(x) = \sqrt{4-x+h}$or$\displaystyle \sqrt{4-(x+h)}?$