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Question

Mathematics Question on Limits

Evaluate the Given limit: limx0\lim_{x\rightarrow 0} ax+xcosxbsinx\frac{ax+xcos\,x}{b\,sin\,x}

Answer

limx0ax+xcosxbsinx\lim_{x\rightarrow 0} \frac{ax+xcos\,x}{b\,sin\,x}
At x = 0, the value of the given function takes the form 0/0.
limx0\lim_{x\rightarrow 0} cos2x1cosx1\frac{cos^2x-1}{cos\,x-1} =\frac{1}{b}$$\lim_{x\rightarrow 0} x(a+cosx)sinx\frac{x(a+cos\,x)}{sin\,x}
=\frac{1}{b}$$\times$$\lim_{x\rightarrow 0}(xsinx\frac{x}{sin\,x}) \times$$\lim_{x\rightarrow 0} (a + cosx)
=1b\frac{1}{b} ×\times (\lim_{x\rightarrow 0}$$\frac{1}{\frac{sin\,x}{x}}) ×\times limx0\lim_{x\rightarrow 0} (a + cosx)
= 1b\frac{1}{b} ×\times (a + cos0) [limx0\lim_{x\rightarrow 0} sinxx\frac{sin\,x}{x} = 1]
= a+1ba+\frac{1}{b}