If `x/acosalpha+y/bsinalpha=1, x/acosbeta+y/bsinbeta=1 and (cos alpha cos beta)/a^2+(sin alpha sin beta)/b^2=0,` then

If x cos alpha + y sin alpha = x cos beta + y sin beta = 2a then cos alpha cos beta =

If x cos alpha + y sin alpha = x cos beta + y sin beta "then" "tan" (alpha + beta)/2=

(sinalpha cos beta+cos alpha sin beta)^2+(cos alpha cos beta-sin alpha sin beta)^2=1

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

If x cos alpha + y sin alpha = x cos beta + y sin beta "then" (sin alpha - cos alpha - sin beta + cos beta)/(sin alpha + cos alpha - sin beta - cos beta)=

If x cos alpha + y sin alpha = x cos beta + y sin beta "then" (2(1-cos (alpha - beta)))/(cos beta - cos alpha)^(2)=

If x cos alpha + y sin alpha=x cos beta+y sin beta,"show that",y=x "tan"(alpha+beta)/2

Prove that (sin alpha cos beta + cos alpha sin beta) ^(2) + (cos alpha coa beta - sin alpha sin beta) ^(2) =1.