91Ó°ÊÓ

Find all real numbers in the interval \([0,2 \pi)\) that satisfy each equation. Round approximate answers to the nearest tenth. $$ 2 \cos ^{2} 2 x-8 \sin ^{2} x \cos ^{2} x=-1 $$

Find all real numbers that satisfy each equation. Round approximate answers to the nearest hundredth. $$ 2 \sec (\pi x)-9=0 $$

Solve each equation. Round approximate answers to the nearest tenth of a degree. $$ \begin{array}{l} (3.6)^{2}=(5.4)^{2}+(8.2)^{2}-2(5.4)(8.2) \cos \alpha \\ \text { for } 0^{\circ}<\alpha<90^{\circ} \end{array} $$

Find all real numbers in the interval \([0,2 \pi)\) that satisfy each equation. Round approximate answers to the nearest tenth. $$ \sin x \cos (\pi / 4)+\cos x \sin (\pi / 4)=1 / 2 $$

Solve each equation. Round approximate answers to the nearest tenth of a degree. $$ \begin{array}{l} (6.8)^{2}=(3.2)^{2}+(4.6)^{2}-2(3.2)(4.6) \cos \alpha \\ \text { for } 90^{\circ}<\alpha<180^{\circ} \end{array} $$

Find all real numbers that satisfy each equation. Round approximate answers to the nearest hundredth. $$ 10 \csc (\pi x / 2)+14=0 $$

Find all real numbers in the interval \([0,2 \pi)\) that satisfy each equation. Round approximate answers to the nearest tenth. $$ \sin (\pi / 6) \cos x-\cos (\pi / 6) \sin x=-1 / 2 $$

Find all real numbers in the interval \([0,2 \pi)\) that satisfy each equation. Round approximate answers to the nearest tenth. $$ \sin 2 x \cos x-\cos 2 x \sin x=-1 / 2 $$

Solve each equation for the indicated variable. Solve \(x=2 \cos (3 y)\) for \(y\) where \(0 \leq y \leq \frac{\pi}{3}\)

Find all real numbers that satisfy each equation. Round approximate answers to the nearest hundredth. $$ 3 \cot (\pi x-1)-1=0 $$