Find the angle between the folowing planes :-
(i) `vecr.(2hati-3hatj+4hatk) = 5` and `vecr.(-hati+hatj) = 1`
(ii) `vecr.(2hati+3hatj-6hatk) = 1` and
`vecr.(hati-2hatj+2hatk) + 3 = 0`
(iii) `x+y-2z=3` and `2x-2y+z+1 = 0`

Answer

(i) `cos^(-1)((-5)/(sqrt(58)))` , (ii) `cos^(-1)((-16)/(21))` , (iii) `cos^(-1)((-2)/(3sqrt(6)))` , (iv) `(pi/2)`