Final Answer
Step-by-step Solution
Specify the solving method
If we directly evaluate the limit $\lim_{x\to a}\left(\frac{\sqrt{b^2-x}-\sqrt{b^2-a}}{x-a}\right)$ as $x$ tends to $a$, we can see that it gives us an indeterminate form
We can solve this limit by applying L'H么pital's rule, which consists of calculating the derivative of both the numerator and the denominator separately
After deriving both the numerator and denominator, the limit results in
The limit of the product of a function and a constant is equal to the limit of the function, times the constant: $\displaystyle \lim_{t\to 0}{\left(at\right)}=a\cdot\lim_{t\to 0}{\left(t\right)}$
Applying the property of exponents, $\displaystyle a^{-n}=\frac{1}{a^n}$, where $n$ is a number
Evaluate the limit $\lim_{x\to a}\left(\frac{1}{\sqrt{b^2-x}}\right)$ by replacing all occurrences of $x$ by $a$
Simplify $-\frac{1}{2}\left(\frac{1}{\sqrt{b^2-a}}\right)$