Задание 15.4

Решите уравнение:
1) cos 2x = 1 2; 2) cos x 5 = 3 2 ; 3) cos 3x 4 = 1.

Answers

1.

cos 2x = 1 22cos 2x1 = 1 22cos 2x = 3 2cos 2x = 3 4cos x = 3 2 x = ±arccos 3 2 +2πnx = ±π 6 +2πn,n

2.

cos x 5 = 3 2 x 5 = ±arccos (3 2 )+2πnx 5 = ±5π 6 +2πnx = ±25π 6 +10πn,n

3.

cos 3x 4 = 13x 4 = ±arccos (1)+2πn3x 4 = π+2πn3x = 4π+8πnx = 4π 3 +8 3πn,n

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2021-11-21 12:27
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