If i .j and k represent unit vectors along the x, y and z axes respectively, then the angle θ

If i .j and k represent unit vectors along the x, y and z axes respectively, then the angle θ between the vectors i +j +k and i +j is equal to
(a) sin-113
(b) sin-123
(c) cos-113
(d) 90°

[@adityaapoorva007]

Thanks a lot sir❤❤❤, i didn't knew the 2nd method.

[@spark468]

Thanku sir for this explanation ❤..

[@jeet7138]

Sir cross product se kyu nahi nikal sakte angle between them

[@sm123_5]

Voh jyada lengthy ho jata hai isliye

[@it_sAnamika]

Sir ye sin inverse smjh nhi aarha...why sin inverse?

[@rootover-1]

cause in the options it was inverse of sin