Ask your own question, for FREE!
Mathematics 8 Online
OpenStudy (anonymous):

Find all solutions in the interval [0,2pi] cos^2x+2cosx+1=0

OpenStudy (anonymous):

call y = cos x. Solve the quadratic equation: y^2 + 2y + 1 = 0. Double root: y = -1. Cos x = y = -1 --> x = Pi. Check: X= Pi; cos x = -1; f(x) = 1 - 2 + 1 = 0 correct.

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Latest Questions
Arriyanalol: i need help
2 days ago 7 Replies 1 Medal
Arriyanalol: CONGRATS to me
2 days ago 8 Replies 2 Medals
Legomaster346: What colleges are good that are near Arab Alabama?
1 week ago 5 Replies 0 Medals
Arriyanalol: i need help
1 week ago 6 Replies 2 Medals
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!