Question
Question: The angle between lines whose direction ratio are 1, 1, 2 and \(\sqrt{3}\) – 1, \(\sqrt{3}\) – 1, 4 ...
The angle between lines whose direction ratio are 1, 1, 2 and 3 – 1, 3 – 1, 4 is
A
450
B
300
C
600
D
900
Answer
600
Explanation
Solution
Apply cos q =a12+b12+c12a22+b22+c22a1a2+b1b2+c1c2
Here a1, b1, c1
̃ 2, –1, 1
a2 , b2, c2 ̃ 1, 1, 2
\ cos q = 662(1)+1(−1)+1(2)=63
cos q = 21=θ=3π