Question

If, the point (2,-1) is on the terminal side of angle 0, find the values of sin0,cos0,tan0

Answer 1

draw the picture and connect with the origin. you will see a right triangle, so all you need is the length of the hypotenuse. we get that by pythagoras:\[\sqrt{2^2+(-1)^2}=\sqrt{5}\]

the coordinates are (2,-1)
\[\cos(\theta)=\frac{2}{\sqrt{5}}\]
\[\sin(\theta)=\frac{-1}{\sqrt{5}}\]
\[tan(\theta)=\frac{-1}{2}\]