Question

11. If the resultant of the vectors 3i - 41 - 56 and
5i +3 +4k makes an angle with z-axis, the
find cos e​

Answer 1

Step-by-step explanation:

Let A=3i+4j+5k and B=5i+3j+4k then the resultant of these vectors, C, can be written as

C=A+B=8i+7j+9k

In terms of direction cosines, C can be written as

C=0.5744i+0.5056j+0.6462k, |C|=13.9284

Then if θ is the angle made by C with x-axis, cos θ=0.5744.