Question

Найдите значение вврадения 8 кл cos^2 30° - sin^2 30° -cos^2 60° - sin^2 60° + cos^2 45° +sin^3 45°

Answer 1

cos^2 30° - sin^2 30° -cos^2 60° - sin^2 60° + cos^2 45° +sin^3 45° =
(√3/2)² - (1/2)² - (1/2)² - (√3/2)² + (1/√2)² + (1/√2)³ =
3/4 - 1/4 -1/4 - 3/4 + 1/2 + 1/(2√2) = 1/(2√2)