Answer:
Step-by-step explanation:
if f(x) = 1/(x+1)
the f(f(x)) means, wherever you see an "x" in the function.
plug in the function again.
so plug in "1/(x+1)" wherever you see an x
so...
1/(f(x) + 1)
1/((1/(x+1))+1)
now you're going to need to fix the denominator.
at the moment... this is what you're denominator looks like.
1/(x+1) + 1
so, combine them. find the LCD
LCD = x + 1
1/(x + 1) + x + 1 / x + 1
x + 2 / x + 1
that's your new denominator.
f(f(x)) = 1 / (x + 2 / x + 1)
because it's 1 / something. all you need to do is get the reciprocal of that "something"
so, what's the reciprocal of x + 2 / x + 1?
x + 1 / x + 2
that's your final answer.
next one.
remember, same deal, everywhere you see an "x" plug in the original function.
f(x) = x/(x+1)
f(f(x)) = f(x) / ( f(x) + 1 )
= [x / (x + 1) ] / [ (x / (x + 1) ) + 1 ]
so, right now this is your denominator.
(x / x + 1) + 1
combine, find the LCD, LCD = x + 1
x / x + 1 + x + 1 / x + 1
2x + 1 / x + 1
that's your new denominator.
so plug it in.
[x / (x + 1) ] / [2x + 1 / x + 1]
this is a little more complicated. but remember, whenever you divide by a fraction, it's the same as multiplying by it's reciprocal
so...
rewrite it like this.
x / (x + 1) * (x + 1) / 2x + 1
the x + 1 cancel out.
and you're left with
x / 2x + 1
hope that helps!
