(2) vector a* vector b= 1, that is, the root number 3*sinA-cosA= 1, cos(A+π/3)=- 1/2, and because of 0.
2. "Let the equation sin(3π-a)= radical number 2*cos(3π-b),
Is the radical number 3*cos(-a)=- radical number 2 *sin(π+B) also true? ",if it is, it should not be a definite value, are you giving less conditions?