In Q4, the terminal ray of our reference angle is the hypotenuse of the right triangle created by connecting the end of the terminal ray to the positive x-axis. Theta is the angle between these 2. In the equation, in the simplest form, if we sub in a 1 for x, then y = -2. That means the distance along the x axis (the base of the right triangle) is 1, and the height of the triangle is -2. We need now to find the measure of the hypotenuse using Pythagorean's Theorem.
![c^2=1^2+(-2)^2](https://img.qammunity.org/2019/formulas/mathematics/high-school/jy3b9ml5us1warnb73mdmddwdm4sd1noqd.png)
and
![c^2=5](https://img.qammunity.org/2019/formulas/mathematics/high-school/xmbnv52o83iojpvum65vmymx4n2zbb9s41.png)
so
![c= √(5)](https://img.qammunity.org/2019/formulas/mathematics/high-school/xhpq4o2rzshaztv24dre5nonmv2z75acut.png)
. The sin of theta is the ratio of the side opposite over the hypotenuse, so
![sin \theta =- (2)/( √(5) )](https://img.qammunity.org/2019/formulas/mathematics/high-school/ydjc1bt7h4aog8suu0q2b7ftp8gfbk9bcd.png)
, and
![csc \theta =- ( √(5) )/(2)](https://img.qammunity.org/2019/formulas/mathematics/high-school/235ovgwk7egws6oifz36idjrk13pmkaqit.png)
.
![cos \theta= (1)/( √(5) )](https://img.qammunity.org/2019/formulas/mathematics/high-school/wb2oaer6xf36twd6g5yjytkecxy61gudea.png)
and
![sec \theta = ( √(5) )/(1)](https://img.qammunity.org/2019/formulas/mathematics/high-school/1bgoo9z93mn1wvh7ospu091cklh8767afc.png)
.
![tan \theta = -(2)/(1)](https://img.qammunity.org/2019/formulas/mathematics/high-school/jtb8srhb90d6r2g3rn3gza6dgnqb0hs5xi.png)
so
![cot \theta =- (1)/(2)](https://img.qammunity.org/2019/formulas/mathematics/high-school/lufljxhvfrcyzqee1543uwe4zn0qgi8t63.png)
. There you go!