f(x)= x/2+x g(x)= 2/x Find f(g(x))
Just replace the x in f(x) with g(x) [that is 2/x]
\[\Large f(g(x)) = f( \frac{2}{x}) = \frac{ \frac{2}{x}}{2}+x\]
understood? can you continue now?
Its the computation I am having trouble with.
wait sorry!! have a question
Ok \[\text{You have \to find } \huge f \left( g(x) \right)\] so its given g(x) = 2/x so replace g(x) with 2/x\[\huge f \left( g(x) \right) = f \left( \frac{2}{x} \right)\] is this clear?
When I replace the terms I get 2/x/2+2/x?
Oh Well YES! that was my mistake & i'm extremely sorry about it
no problem, please continue.
\[\large f(x)= \frac{x}{2}+x\]\[\Large f \left( \frac{2}{x} \right) = \frac{\left( \frac{2}{x} \right)}{2}+ \left( \frac{2}{x} \right)\]
are you having any trouble in simplifying it?
yes
tell me what is \(\large \frac{\left( \frac{2}{x} \right)}{2}\)
4x
4/x
i hope you know that 2 can be written as 2/1 so here we are dividing a fraction by another fraction \[ \large \frac{\left( \frac{2}{x} \right)}{ \left( \frac{2}{1} \right)} \]so here we take reciprocal \[ \large \frac{\left( \frac{2}{x} \right)}{ \left( \frac{2}{1} \right)} = \frac{2}{x} \times \frac{1}{2}\] so what do you get now?
2/2x
Yes ,what is 2/2x
(2/x)/2
Noo... 2/2x can be simplified \[\frac{2}{2 \times x} = \frac{\cancel{2}}{\cancel{2} \times x} = ?\](we are cancelling out because 2/2=1)
1/x
Right!!! :D Now what do you have ?
\[\Large f \left( \frac{2}{x} \right) = \frac{\left( \frac{2}{x} \right)}{2}+ \left( \frac{2}{x} \right) = \frac{1}{x} + \frac{2}{x}\] Is this clear?
3/x
Very Good! :D
i hope you understood!
yes but my text gives the answer 1/x+1
wait.. is your question \[f(x)= \frac{x}{2+x}~~~or~~~ f(x)= \frac{x}{2} + x\]
The first.
@Diyadiya
i think its the first one, then you'll get the answer 1/x+1 same way we replace g(x) in f(g(x)) by 2/x \[\Large f(\frac{2}{x}) = \frac{\left( \frac{2}{x} \right)}{2+\left( \frac{2}{x} \right)}\] Lets do the denominator first what is 2 + 2/x ?\[2+\frac{2}{x}~~=~~ \frac{2}{1}+ \frac{2}{x}~~=~~\frac{2 \times x}{1 \times x} + \frac{2}{x} ~~= \frac{2x}{x}+ \frac{2}{x}\]**i multiplied by x inorder to have common denominator without which you cannot add two fractions
yes
\[\Large f(\frac{2}{x})= \frac{\left( \frac{2}{x} \right)}{\frac{2x}{x}+ \frac{2}{x}}= \frac{\left( \frac{2}{x} \right)}{\frac{2x+2}{x}}\] Now can you take reciprocal ?
2/x*x/2x+2= 2/2x+2?
factor out the 2
Yes :D
:)
there you have the answer :D
thank you
Anytime :) sorry i misread the question in the beginning
no problem your fantastic.
Haha Thanks
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