PQ and QR are two focal chords of an ellipse and the eccentric angles of P,Q,R are `2alpha, 2beta, 2 gamma`, respectively then `tan beta gamma` is equal to

If the direction angles of a line are alpha, beta and gamma respectively, then cos 2 alpha + cos 2 beta + cos 2gamma is equal to

In Delta PQR, Q is a right angle, PQ = 3 and QR = 4. If angle P = alpha and R = beta, then tan beta is equal to

If alpha and beta are the eccentric angles of the extremities of a focal chord of an ellipse,then prove that the eccentricity of the ellipse is (sin alpha+sin beta)/(sin(alpha+beta))

If alpha+beta=(pi)/(2) and beta+gamma=alpha, then tan alpha equals

If alpha+beta=(pi)/(2) and beta+gamma=alpha then tan a equals-