SOLUTION: What is the minimum value of cos(theta) + 2cos(theta +240)

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Question 1143227: What is the minimum value of cos(theta) + 2cos(theta +240)
Answer by math_helper(2461)   (Show Source): You can put this solution on YOUR website!



Set dy/dt = 0 to find critical points:

dy/dt is zero at t = -90 degrees (and every +/- 180 degrees added to that)
zeros are at t = degrees

n t (deg) y
--- ------- ---
-1 -270
0 -90
1 90

The minimum value is (approx. -1.732051) at t=-90 degrees





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