Mathematics

Mathematics

Problem

lim⁡x→0ex2−cos⁡xx2=\lim_{x \rightarrow 0} \frac{e^{x^2} - \cos x}{x^2} = (a) 32\frac{3}{2} (b) −12-\frac{1}{2} (c) 1 (d) None of these
Intuitive explanation

This is a limit of an indeterminate form 00\frac{0}{0}, so you'll need Taylor series. The key insight is that both the numerator and denominator involve x2x^2 terms, so expand ex2e^{x^2} and cos⁡x\cos x around x=0x=0 and keep terms up to x2x^2 (or slightly higher to see the pattern). Once you subtract and simplify, the x2x^2 in the denominator will cancel with the leading term in the numerator, revealing the limit.

Intuitive explanation

This is a limit of an indeterminate form 00\frac{0}{0}, so you'll need Taylor series. The key insight is that both the numerator and denominator involve x2x^2 terms, so expand ex2e^{x^2} and cos⁡x\cos x around x=0x=0 and keep terms up to x2x^2 (or slightly higher to see the pattern). Once you subtract and simplify, the x2x^2 in the denominator will cancel with the leading term in the numerator, revealing the limit.

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