Question

Sin7x-sin3x-cos5x=0

Срочно

Answer 1

sin7x - sin3x - cos5x = 0

2sin2x cos5x - cos5x = 0

cos5x (2sin2x - 1) = 0

cos5x = 0 2sin2x = 1

5x = π/2 + πn sin2x = 1/2

x = π/10 + πn/5 2x = π/6 + 2πk

2x = 5π/6 + 2πk

x = π/12 + πk

x = 5π/12 + πk

Ответ : x = π/10 + πn/5 , n € Z ; x = π/12 + πk , x = 5π/12 + πk , k € Z