Under what condition will the angle between two regression lines become zero?

Angle between two lines

Under what conditions angleD = angleD_m

The regression coefficient of y on x is 2/3 and that of x on y is 4/3. The acute angle between the two regression lines is tan ^(-1) k, wher k is equal to :

If the angle between two lines regression is 90^(@) , then it represents

If the angle between two lines regression is 90^(@) , then it represents

If the angle between two lines regression is 90^(@) , then it represents

If the regrassion coefficient of Y on X is 1.6 that of X on Y is 0.4 , and theta be the angle between two regression lines , find the value of tan theta

The angle between the regression lines: x-2y+3=0, 4x-5y+1=0 is