The equation ${\sin ^2}\theta = \frac{{{x^2} + {y^2}}}{{2xy}},x,y, \ne 0$ is possible if
$x = y$
$x = \, -y$
$2x = y$
none of these
Find the value of the trigonometric function $\cot \left(-\frac{15 \pi}{4}\right)$
If $A = 130^\circ $ and $x = \sin A + \cos A,$ then
Find the value of the trigonometric function $\tan \frac{19 \pi}{3}$.
Find the degree measure of the angle subtended at the centre of a circle of radius $100 \,cm$ by an arc of length $22\, cm$ ( Use $\pi=\frac{22}{7}$ ).
Find the value of:
$\sin 75^{\circ}$