[" The incentre of the triangle formed by the "],[" lines "x cos alpha+y sin alpha=pi,x cos beta+y sin beta=pi],[x cos gamma+y sin gamma=pi" is "(h,k)" then "h+k=]

The incetre of the triangle formed by the lines x cos alpha+y sin alpha=pi,x cos beta+y sin beta=pi,x cos gamma+y sin gamma=pi is (h,k) then h+k=

The orthocentre of triangle formed by (a cos alpha,a sin alpha),(a cos beta,a sin beta),(a cos gamma,a sin gamma) is

If origin is the orthocentre of a triangle formed bythe points (cos alpha, sin alpha,0), (cos beta, sin beta,0), (cos gamma, sin gamma,0) then sumcos(2alpha-beta-gamma)= -

If origin is the orthocenter of a triangle formed by the points (cos alpha*sin alpha,0)*(cos beta,sin beta.0),(cos gamma,sin gamma,0) then sum cos(2 alpha-beta-gamma)=

If (0,0) is orthocentre of triangle formed by A(cos alpha,sin alpha),B(cos beta,sin beta),C(cos gamma,sin gamma) then /_BAC=

If (0,0) is orthocentre of triangle formed by A(cos alpha,sin alpha),B(cos beta,sin beta),C(cos gamma,sin gamma) then /_BAC is

If x cos alpha + y sin alpha = x cos beta + y sin beta = a, 0

Prove that the area of the parallelogram formed by the lines x cos alpha+y sin alpha=p,x cos alpha+y sin alpha=q,x cos beta+y sin beta=r and x cos beta+y sin beta=sis+-(p-q)(r-s)csc(alpha-beta)