Дан треугольник \( A B C \), в котором \( \angle C=90^{\circ} \), а \( \sin B=\frac{2 \sqrt{2}}{10} \). Найди \( \cos ^{2} B \).

Which points are the same as \( \left(18,19^{\circ}\right) \) ? Check all that apply. \( \begin{array}{ll}\left(-18,-161^{\circ}\right) & \left(-18,199^{\circ}\right) \\ \left(18,-341^{\circ}\right) & \left(18,199^{\circ}\right) \\ \left(-18,-379^{\circ}\right) & \left(18,379^{\circ}\right)\end{array} \)

Solve \( 2 \cos ^{2}(t)-3 \cos (t)+1=0 \) for all solutions. \( t=\square+2 k \pi \); Select an answer Give your answers as exact values in a list separated by commas. \( > \) Next Question

Which points are the same as \( \left(15,11^{\circ}\right) \) ? Check all that apply. \( \begin{array}{ll}\left(15,191^{\circ}\right) & \left(15,-349^{\circ}\right) \\ \left(15,371^{\circ}\right) & \left(-15,191^{\circ}\right)\end{array} \)

Prove that: \( \frac{\sin A+\sin 2 A}{1+\cos A+\cos 2 A}=\tan A \)

(i) \( \sin ^{2} 60^{\circ}+\cos ^{2} 60^{\circ}=1 \)