Question

Solve ${\csc }^{2}45.{\sec }^{2}30.{\sin }^{2}90.\cos 60=1\frac{1}{3}$

Answer 1

${\csc }^{2}45.{\sec }^{2}30.{\sin }^{2}90.\cos 60$

$={\left(\sqrt{2}\right)}^2.{\left(\frac{2}{\sqrt{3}}\right)}^2.1^2.{\left(\frac{1}{2}\right)}^2$

$=2.\frac{4}{3}.1.\frac{1}{4}$

$=\frac{2}{3}$

$=1\frac{1}{3}$