The number of roots of the equation $x ^ { 2 } + \sin ^ { 2 } x = 1$ in the closed interval $\left[ 0 , \frac { \pi } { 2 } \right]$ is (a) 0 (b) 1 (c) 2 (d) 3
(b) Draw graphs of $y = \cos x$ and $y = \pm x$ and find the number of points of intersections.
The number of roots of the equation $x ^ { 2 } + \sin ^ { 2 } x = 1$ in the closed interval $\left[ 0 , \frac { \pi } { 2 } \right]$ is\\
(a) 0\\
(b) 1\\
(c) 2\\
(d) 3