Question

Show that the lines whoes dc are proportional to (2,1,1)(4,√3-1,-√3-1)are inclined to one another at angle π/3

Answer 1

Answer:

We can find the angles between the two lines by using dot product.

D(2,1,1)  C(4,√3-1, -√3-1)

8+√3-1-√3-1= (√(4+1+1))(√(16+3+1+3+1)cosФ

6=(√6)(√24)cosФ

The value of Ф=π/3