Question

The number of points in $(-\infty ,\infty )$, for which $x^2-x\sin x-\cos x=0$, is

• A. $6$
• B. $4$
• C. $2$
• D. $0$

Answer 1

Answer: (C)

$2$

Better approach is with graphs, considering graphs in equation we get

$x^2-xsinx-cosx=0$

$x^2=xsinx+cosx$

Let F(x) = $x^2$ and G(x) = $xsinx+cosx$

The graph intersects at two points hence the answer is 2.