Question

7.
Find the angle between two lines whose direction ratios are
1, 1, 2 and 2, - 1, 2.​

Answer 1

Step-by-step explanation:

cos© =

a1a2+b1b2+c1c2/

(√a1^2+b1^2+c1^2)(√a2^2+b2^2+c2^2)

cos©=

1(2)+1(-1)+2(2)/(√1^2+1^2+2^2)(√2^2+(-1)^2+2^2)

=>2-1+4/(√1+1+4)(4+1+4)

=>5/(√6)(√9)

=>5/3√6

© = cos^-1(5/3√6)