A=cos¶i+sin¶j, B=cos2¶i-sin2¶j then fibd angle between A×B?

Question

this is a question of vector.&¶=theta

Answer 1

 

cos(pi) = -1

sin(pi) = 0

 

cos (2*pi) = 1

sin(2*pi) = 0

 

A = -1(1,0) + 0(0,1) = (-1,0) + (0,0) = (-1,0)

 

B = 1(1,0) - 0(0,1) = (1,0) - (0,0) = (1,0)

 

|A| = 1 and |B|=1

 

Per the right hand rule, the perpendicular is at (0,1) and the cross product is zero

since the vectors are parallel but opposite on the x-axis.

 

0 = A x B = |A||B| sin T * (0,1) = 1*1*sin T * |(0,1)|

 

0 = sin T 

T = 180