Question

(6A + 4B)cos3x + (4A - 6B)sin3x + x((-5A)sin3x + (12A - 5B)cos3x) + (25A*sin3x + 25B*cosX)
решите плиз:)

Answer 1

(sin3x*cosx-sinx*cos3x)()=0
(sin3x*cosx-sinx*cos3x)=sin 2x
sin2x=0
x=πN/2
5x-x²=0
x=0
x=5
x(5-x)>=0
==============0=========5==========
-------------------------       +++++++   -----------
ОДЗ x=[0 5]
x=πN/2  N=0, 1 , 2 , 3
x=5