Find the scalar projection of the vector ^i+3^j+7^k on the vector 2^i−^j+6^k.

The scalar projection of vector ^i+3^j+7^k on the vector 2^i−^j+6^k is
( ^i+3^j+7^k)⋅(2^i−^j+6^k) / |2^i−^j+6^k|
= (2 -3 +42) / √(4+1+36)
= 41 / √41
= √41
= 6.403