Question

Если 6sin^2a=1, то 6cos^2a=?

Answer 1

$6 \sin {}^{2} (a) = 1 \Rightarrow \sin {}^{2} (a) = \frac{1}{6} \\ \sin {}^{2} (a) + \cos {}^{2} (a) = 1 \\ \cos {}^{2} (a) = 1 - \sin {}^{2} (a) \\ 6 \cos {}^{2} (a) = 6 - 6 \sin {}^{2} (a) \\ 6 \cos {}^{2} (a) = 6 - 6 \times \frac{1}{6} = 6 - 1 = 5$

ответ: 5