Questions: If f(x)=√(x-1) and g(x)=1/(x^2+1) then g[f(x)]=
a) 1/x
b) 1/√(x-1+1)
c) 1/(x-1)
d) -1/√(x^2+1)
Transcript text: If $f(x)=\sqrt{x-1}$ and $g(x)=\frac{1}{x^{2}+1}$ then $g[f(x)]=$
a) $\frac{1}{x}$
b) $\frac{1}{\sqrt{x-1+1}}$
c) $\frac{1}{x-1}$
d) $\frac{-1}{\sqrt{x^{2}+1}}$
Solution
Solution Steps
To find g[f(x)], we need to substitute f(x) into g(x). Given f(x)=x−1 and g(x)=x2+11, we substitute x−1 into g(x) to get g(x−1).
Step 1: Define the Functions
Given the functions:
f(x)=x−1g(x)=x2+11
Step 2: Substitute f(x) into g(x)
We need to find g(f(x)). Substitute f(x)=x−1 into g(x):
g(f(x))=g(x−1)=(x−1)2+11
Step 3: Simplify the Expression
Simplify the expression:
g(x−1)=x−1+11=x1
Final Answer
The answer is x1, which corresponds to option (a).