The number of distinct real roots of … in the interval … is :

Matrices and Determinants

JEE Main 2021 · 25 Jul, Evening shift · Q4466

MathematicsMedium244×since 2002Q4466

The number of distinct real roots of

\left| {\matrix{ {\sin x} & {\cos x} & {\cos x} \cr {\cos x} & {\sin x} & {\cos x} \cr {\cos x} & {\cos x} & {\sin x} \cr } } \right| = 0

in the interval

- {\pi \over 4} \le x \le {\pi \over 4}

is :

JEE Main 2021 · 25 Jul, Evening shift · Q4466

MathematicsMedium244×since 2002Q4466

The number of distinct real roots of

\left| {\matrix{ {\sin x} & {\cos x} & {\cos x} \cr {\cos x} & {\sin x} & {\cos x} \cr {\cos x} & {\cos x} & {\sin x} \cr } } \right| = 0

in the interval

- {\pi \over 4} \le x \le {\pi \over 4}

is :