Question

Solve sin^2θ−4sinθ−5=0 for 0°≤θ≤360°

Answer 1

Answer:

$\theta=270^\circ$

Step-by-step explanation:

Given Equation and Parameters

$sin^2\theta-4sin\theta-5=0,\: 0^\circ\leq\theta\leq 360^\circ$

Calculation

Let $u=sin\theta$, thus:

$u^2-4u-5=0\\\\(u+1)(u-5)=0\\\\u=-1,\: u=5$

$sin\theta=-1\\\\\theta=270^\circ$

$sin\theta=5\\\\\theta=unde fined$

Conclusion

$\theta=270^\circ$