Question

formula derivation for plane angle ​

Answer 1

Calculation of Angle Between Two plane in the Cartesian Plane. Let A1 x + B1 y + C1z + D1 = 0 and A2x + B2y + C2 z + D2 = 0 be the equation of two planes aligned to each other at an angle θ where A1, B1, C1 and A2, B2, C2 are the direction ratios of the normal to the planes.