Question

5sin5t-2cos5t=0

 

cos^2(Pi/8-x)-cos^2(Pi/8+x)=1/2

Answer 1

1) 5sin(5)t-2cos(5t)=0

     sin(5t)=2/5cos(5t)

     2cos(5t)=5sin(5t)

2)cos^2(Pi/8-x)-cos^2(Pi/8+x)=1/2

4sin(П/8)cos(П/8)=1/2

√2  sin(x)cos(x)=1/2

√2  sin(2x)=1

 

 

x=1/8(8Пn*П),   n Е Z

x=1/8(8Пn*3П),   n Е Z