Find the value of ${\cos }^{2}0+{\cos }^2\frac{\mathrm{\pi }}{6}+{\cos }^2\frac{\mathrm{\pi }}{3}+{\cos }^2\frac{\mathrm{\pi }}{2}$

Find the other trigonometric functions if $\mathrm{cos\theta }=-\frac{3}{5}$ and $180°<\mathrm{\theta }<270°$

Find the other trigonometric functions if $\sec A=-\frac{25}{7}$ and $90°<A<180°$

Find the other trigonometric functions if $\cot x=\frac{3}{4}$ and $180°<x<270°$

Find the other trigonometric functions if $\tan x=\frac{-5}{12}$ and $270°<x<360°$

Eliminate $\mathrm{\theta }$ from the following, $x=3 \mathrm{sec\theta },y=4 \mathrm{tan\theta }$.