find tantheta and sectheta
- Thread starter aplubin
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skeeter
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cos(2t) = -3/4
cos(2t) = 2cos<sup>2</sup>t - 1
2cos<sup>2</sup>t - 1 = -3/4
2cos<sup>2</sup>t = 1/4
cos<sup>2</sup>t = 1/8
since pi < 2t < pi/2, pi/2 < t < pi/4 ... so theta (t) is a quad I angle.
cost = 1/[2sqrt(2)] ... sect = 2sqrt(2)
tan<sup>2</sup>t + 1 = sec<sup>2</sup>t
tan<sup>2</sup>t + 1 = 8
tant = sqrt(7)
cos(2t) = 2cos<sup>2</sup>t - 1
2cos<sup>2</sup>t - 1 = -3/4
2cos<sup>2</sup>t = 1/4
cos<sup>2</sup>t = 1/8
since pi < 2t < pi/2, pi/2 < t < pi/4 ... so theta (t) is a quad I angle.
cost = 1/[2sqrt(2)] ... sect = 2sqrt(2)
tan<sup>2</sup>t + 1 = sec<sup>2</sup>t
tan<sup>2</sup>t + 1 = 8
tant = sqrt(7)