CALCULUS
posted by Stumped Student on .
If cos(t)=–7/9, find the values of the following trigonometric functions.
Note: Give exact answers, do not use decimal numbers. The answer should be a fraction or an arithmetic expression.
a) cos (2t)
b) sin (2t)
c) cos(1/2)
d) sin (1/2)
i don't even know what this question is asking me to find!

I will do one for you. It is asking you to apply the double and half angle formulas.
Cos2t=sin^t cos^2 t
Now do you know how to get the sint, given cost?
Use pythoregean theorm.