If $\sin \theta=\frac{-1}{2}$ and $\theta$ lies in Quadrant IV, find the values of all the other five trigonometric functions.
Given: $\sin \theta=\frac{-1}{2}$
Since, $\theta$ is in IVth Quadrant. So, sin and tan will be negative but cos will be positive.
We know that,
$\sin ^{2} \theta+\cos ^{2} \theta=1$
Putting the values, we get
$\left(-\frac{1}{2}\right)^{2}+\cos ^{2} \theta=1$ [given]
$\Rightarrow \frac{1}{4}+\cos ^{2} \theta=1$
$\Rightarrow \cos ^{2} \theta=1-\frac{1}{4}$
$\Rightarrow \cos ^{2} \theta=\frac{4-1}{4}$
$\Rightarrow \cos ^{2} \theta=\frac{3}{4}$
$\Rightarrow \cos \theta=\sqrt{\frac{3}{4}}$
$\Rightarrow \cos \theta=\pm \frac{\sqrt{3}}{2}$
Since, $\theta$ in IV th quadrant and $\cos \theta$ is positive in IV $^{\text {th }}$ quadrant
$\therefore \cos \theta=\frac{\sqrt{3}}{2}$
Now,
$\tan \theta=\frac{\sin \theta}{\cos \theta}$
Putting the values, we get
$\tan \theta=\frac{-\frac{1}{2}}{\frac{\sqrt{3}}{2}}$
$=-\frac{1}{2} \times\left(\frac{2}{\sqrt{3}}\right)$
$=-\frac{1}{\sqrt{3}}$
Now,
$\operatorname{cosec} \theta=\frac{1}{\sin \theta}$
Putting the values, we get
$\operatorname{cosec} \theta=\frac{1}{-\frac{1}{2}}$
$=-2$
Now,
$\sec \theta=\frac{1}{\cos \theta}$
Putting the values, we get
$\sec \theta=\frac{1}{\frac{\sqrt{3}}{2}}$
$=\frac{2}{\sqrt{3}}$
Now,
$\cot \theta=\frac{1}{\tan \theta}$
Putting the values, we get
$\cot \theta=\frac{1}{-\frac{1}{\sqrt{3}}}$
$=-\sqrt{3}$
Hence, the values of other trigonometric Functions are: