Question

if a vector abar makes an anglea 45 dgrees and 60 degrees with x and y axis respectively then the angla made by it with z axis is

Answer 1

Answer:

We know that cos

2

α+cos

2

β+cos

2

γ=1,

i.e., sum of the squares of the direcction cosines is unity,

Where α,β,γ are the angles made by a line with positive direction of the axes,

⟹

4

1

+cos

2

β+

4

1

=1

⟹cos

2

β=

2

1

cosβ=

2

1

or −

2

1

⟹β=45

0

or135

0