Question
Solve the equation on the interval [0,360) cos^2t+2cos(t)+1=0
Answers
Reiny
cos^2t+2cos(t)+1=0
(cost + 1)^2 = 0
cost + 1 = 0
cost = -1
t = 270°
(cost + 1)^2 = 0
cost + 1 = 0
cost = -1
t = 270°