Question

solve cos 3 theta = -1 (0 13 years ago

Answer 1

how?

Answer 2

jessie is mixing up sin and cos.
Cos(3theta)=-1
so, What angle gives you -1 when put into theta? Its 180 degrees, or pi.
and you want 3 times theta to equal -1so theta is 60 gegrees. or pi/3

Answer 3

cos (3x) = -1 --> 3x = arc cos -1 (negative angle in cos becomes positive)
--> 3x = 0 + 2k pi with k Є N
--> x = (2/3)k pi
if k = 0 --> x = 0
if k = 1 --> x = (2/3) pi
if k = 2 --> x = (4/3) pi

A = { 0 ; (2/3) pi ; (4/3) pi }

Answer 4

sry got confused earlier