Question

Cos X +1 / cos X=40, find the value of cos square X +1/ cos square X
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Answer 1

This is pseudo-trig. It has a trig function but it's irrelevant.

Let y = cos X

y + 1/y = 40

Squaring,

y² + 2(y)(1/y) + 1/y² = 1600

y² + 2 + 1/y² = 1600

y² + 1/y² = 1598

cos² X + 1/cos²X = 1598

Answer: 1598