1) sin²45° – sin²30° = cos60° – cos-45°. - вопрос №17411468145306045 от Sobennikovoleg 27.02.2020 19:11

Question

Алгебра: 1) sin²45° – sin²30° = cos60° – cos-45°.​

Sobennikovoleg · Answer

1) sin30° cos60° - sin²45° = 1/2•1/2 - 1/2 = -1/4

2) 2cos180° - sin²270° = 2•(-1) - 1 = -3

3) cos30° sin60° + cos² 45° = 1/2•1/2 + 1/2 = 1/4 + 1/2 = 3/4.

4) 3sin 90° - cos² 0° = 3•1 - 1 = 2

Объяснение:

1) sin²45° – sin²30° = cos60° – cos-45°.​