Question

Решите уравнения 

1)sin2x+sin4x=0

2)cos3x-cos5x=0 

3)sin3x+cos3x=0

решите хоть один плиз))

 

 

Answer 1

1) sin2x + 2sin2x*cos2x = 0

sin2x ( 1 + 2 cos2x) = 0

sin2x = 0                           или            1 + 2cos2x =0

2x = (-1)^n * П/2 +2Пn                        cos2x = -1/2

x = (-1)^n * П/4 +Пn                            2x = +- * 2П/3 + 2П/n

                                                          x = +- * п/3 + Пn

 

3) sin3x+cos3x=0 / cos3x не равн. 0

tg3x + 1 = 0

tg3x = -1

3x = -П/4 + Пn

x = -П/12 + П/3n