, where ,…

MATHEMATICS · Single correct · A Level · Mathematics · Differentiation · Differentiation

Problem

\displaystyle\lim_{x\to a^-}\frac{\sqrt{x-b}-\sqrt{a-b}}{x^2-a^2}

, where

a>b

, is (1)

\frac{1}{4a}

(2)

\frac{1}{a\sqrt{a-b}}

(3)

\frac{1}{2a\sqrt{a-b}}

(4)

\frac{1}{4a\sqrt{a-b}}