Question

Find the angle between the straight lines-
\[xcos \alpha +ysin \alpha = p\]
\[xcos \beta +ysin \beta = q\]

Answer 1

I hava method, donno whether its the best...
find slope of each line, m1,m2
angle between lines is = tan^-1 ((m1-m2)/(1+m1m2))

Answer 2

i know that, but how to find the slope.

Answer 3

isolate y
slope of y=mx+c is m

Answer 4

i think u can isolate y

Answer 5

ok got it

Answer 6

good :)

Answer 7

is it right ? \[\tan^{-1}( (\cot \beta -\cot \alpha) / (1 +\cot \alpha \cot \beta))\]

Answer 8

yes