Question
Determine $\lim _{x \rightarrow 1}\left\{\frac{x^{2}+3 x-4}{x^{2}-7 x+6}\right\}$The first step is to substitute $x=1$ into both numerator and denominator. In this case we obtain $\frac{0}{0}$. It is only when we obtain such a result that we then use L'HĂ´pital's rule. Hence applying L'HĂ´pital's rule,$$\lim _{x \rightarrow 1}\left\{\frac{x^{2}+3 x-4}{x^{2}-7 x+6}\right\}=\lim _{x \rightarrow 1}\left\{\frac{2 x+3}{2 x-7}\right\}$$i.e. both numerator and denominator have been differentiated$$=\frac{5}{-5}=-1$$
Step 1
We get $\frac{1^{2}+3(1)-4}{1^{2}-7(1)+6}$, which simplifies to $\frac{0}{0}$. Show more…
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