Find the acute angle between the following planes :

(i) and

(ii) and

(iii) and

(iv) and

To find the angle between two planes, we simply find the angle between the normal vectors of planes. So if n1 and n2 are normal vectors and θ is the angle between both then,

(i)On comparing with the standard equation of planes in vector form

Then

(ii) On comparing with the standard equation of planes in vector form

Then

(iii) On comparing with the standard equation of planes in vector form

Then

(iv)On comparing with the standard equation of planes in vector for

Then