For each of the following angles (in radian measure), find the cosine of the angle.
Note: Your answer must be in EXACT form: it cannot contain trig functions, and it cannot contain decimals; it must be given as an integer or a tion. If the answer involves square roots use √. For example, the square root of 2 should be written as √(2).

a. Cosine of π/6 is (√3)/2.
b. Cosine of π/4 is (√2)/2.
c. Cosine of π/3 is 1/2.
d. Cosine of π/2 is 0.
e. Cosine of π is -1.
f. Cosine of 2π is 1.