If cos(t)=–7/9, find the values of the following trigonometric functions.

Question

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!

Answer 1

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.