WBJEE · Maths · Determinants
Let \(f(x)=\left|\begin{array}{ccc}\cos x & x & 1 \\ 2 \sin x & x^3 & 2 x \\ \tan x & x & 1\end{array}\right|\), then \(\lim _{x \rightarrow 0} \frac{f(x)}{x^2}=\)
- A 2
- B -2
- C 1
- D -1
Answer & Solution
Correct Answer
(B) -2
Step-by-step Solution
Detailed explanation
Hint : \(\begin{aligned} & f(x)=\left(x^3-2 x^2\right) \cos x+\tan x\left(2 x^2-x^3\right) \\ & \begin{aligned} \lim _{x \rightarrow 0} \frac{f(x)}{x^2} & =\lim _{x \rightarrow 0}(x-2) \cos x+\tan x(2-x) \\ & =-2 \end{aligned} \end{aligned}\)
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