Question

Sin3x=cos4x. .…………………

Answer 1

sin3x-sin(π/2-4x)=0
2sin(7x/2-π/4)cos(π/4-x/2)=0
sin(7x/2-π/4)=0⇒7x/2-π/4=πn⇒7x/2=π/4+πn⇒x=π/14+2πn/7
cos(π/4-x/2)=0⇒sin(x/2+π/4)=0⇒x+π/4=πn⇒x/2=-π/4+πn⇒x=-π/2+2πn