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Mathematics 7 Online
OpenStudy (anonymous):

what values for theta(0<=theta<=2pi) satisfy the equation? 4cos theta + 1= 2cos theta

OpenStudy (rulnick):

Solve for cos theta to get: cos theta = -1/2 Do you know which angles have a cosine equal to -1/2?

OpenStudy (anonymous):

i got that part the -1/2 but am stuck after that?

OpenStudy (anonymous):

is it 2pi/3 and 4pi/3

OpenStudy (rulnick):

The angles that have cosine -1/2 are 120 degrees and 240 degrees, or 2pi/3 and 4pi/3.

OpenStudy (rulnick):

Yes!

OpenStudy (anonymous):

oh an 0

OpenStudy (anonymous):

thank you :)

OpenStudy (rulnick):

welcome

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