Question

5-5sin3(пи-x)=cos^2(пи-3x)

Answer 1

5-5sin3(π-x)=cos²(π-3x)
5-5sin3x-cos²3x=0
5-5sin3x-1+sin²3x=0
sin²3x-5sin3x+4=0
sinx=a
a²-5a+4=0⇒a1+a2=5 U a1*a2=4
a1=1⇒sin3x=1⇒3x=π/2+2πn⇒x=π/6+πn/3
a2=4⇒sin3x=4∉[-1;1]