Find the exact value of each expression, if possible, without using a calculator. (if an answer is undefined, enter undefined.)
(a) arctan(1)
(b) arccos(−1)

find the exact value of each expression, if possible, without using a calculator. (if an answer is undefined, enter undefined.)
(a) cos^−1(−2)
(b) sin^-1(-square root 2/2)

use a calculator to approximate the value of the expression, if possible. round your answer to the nearest hundredth. (enter your answer in radians. if an answer is undefined, enter undefined.)
tan−1(6.8)