How do you solve the equation $sec^2theta-2sectheta-3=0$ for $[-180^circ, 180^circ)$ ?

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Answer 1 · 2017-02-05T14:29:00

$theta= +-70.55, +-180$

$sec^2theta -2sectheta -3 =0$

Let $x=sectheta$

$x^2 -2x -3 =0$

$(x-3)(x+1) =0$

$x=3$

$x=-1$

$sectheta=3$

$costheta = 1/3$

$theta = 70.55, -70.55$

$costheta = -1$

$theta = 180, -180$

How do you solve the equation sec^2theta-2sectheta-3=0sec^2theta-2sectheta-3=0 for [-180^circ, 180^circ)[-180^circ, 180^circ)?