If sin (t) = 3 over 8 and t is in the 2nd quadrant, find cos (t)

Question

Homework for pre calculus

Answer 1

The other leg of a right triangle is sqrt(55).

The magnitude of the cos is (1/8) sqrt(55) and the sign is - because the cos is negative in quadrant II.

You might like to remember the mnemonic AllSinTanCos for the function which is + is quadrant 1,2,3, and 4 respectively.