Question

find the angle between the lines whose direction ratios are (1,1,2) (root3 -root3,0)

Answer 1

Answer:

The direction ratios are (1,1,2) and (

3

−1,−

3

−1,4)

Angle between them is given by

cosθ=

1

2

+1

2

+2

2

(

3

−1)

2

+(−

3

−1)

2

+4

2

1(

3

−1)+1(−

3

−1)+2/4)

=

6

8+16

3

−1−

3

−1+8

=

6

24

6

=

144

6

=

12

6

=

2

1

cosθ=

2

1

⇒θ=

3

π

=60