Question bank/JEE Main/Mathematics

JEE MainMathematicsModerateLimits, continuity and derivability

lim⁡x→−1\mspace2mu(11+x−31+x3)\lim_{x \rightarrow - 1}\mspace{2mu}\left( \frac{1}{1 + x} - \frac{3}{1 + x^{3}} \right)
is equal to

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lim⁡x→−1\mspace2mu(11+x−31+x3)=lim⁡x→−1\mspace2mu1+x2−x−3(1+x)(x2−x+1)\lim_{x \rightarrow - 1}\mspace{2mu}\left( \frac{1}{1 + x} - \frac{3}{1 + x^{3}} \right) = \lim_{x \rightarrow - 1}\mspace{2mu}\frac{1 + x^{2} - x - 3}{(1 + x)\left( x^{2} - x + 1 \right)}
=lim⁡x→−1\mspace2mu(x+1)(x−2)(x+1)(x2−x+1)=−33=−1= \lim_{x \rightarrow - 1}\mspace{2mu}\frac{(x + 1)(x - 2)}{(x + 1)\left( x^{2} - x + 1 \right)} = \frac{- 3}{3} = - 1

Source: Grass-G / M-11 Mathematics Paper-2 1Nov.docx

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