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The equation \sin x+x \cos x=0 has atleast one root in the interval

 

Option: 1

\left(-\frac{\pi}{2}, 0\right)


Option: 2

(0, \pi)


Option: 3

\left(-\frac{\pi}{2}, \frac{\pi}{2}\right)


Option: 4

None of these 


Answers (1)

best_answer

Consider the function f(x) is given by 

                   f(x)=\int(\sin x+\cos x) d x=x \sin x

We observe that 

                    f(0)=f(\pi)=0

Therefore, 0\: \text{and}\: \pi are two roots of f(x)=0.

Consequently, f(x)=0 i.e., \sin x+x \cos x=0 has at least one root in (0,\pi).

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Kshitij

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