Question

Question #0ad85

Answer 1

0.416

Explanation:

cos t = 0.8415 --> `cos ^2 t = 0.7081`
Use trig identity:
`cos 2a = 2cos^2 a - 1`
`cos 2t = 2(0.7081) - 1 = 1.416 - 1 = 0.416`