Question

The value of the expression $({\cos }^2{23}^0-{\sin }^2{67}^0)$ is positive.

Answer 1

${\cos }^2({90}^{\circ }-{67}^{\circ })-{\sin }^2\left({67}^{\circ }\right)$
$={\sin }^2\left({67}^{\circ }\right)-{\sin }^2\left({67}^{\circ }\right)$
$=0$
in $\sin \theta$, value of $\theta$ increases, value of $\sin \theta$ increases