Let S and S′ be the focii of an ellipse. At any point P on the ellipse if SPS′<900 then the eccentricity is:
The tangent at any point P on the ellipse meets the auxiliary
circle in two points which subtend right angle at the centre of the ellipse. If θ be the eccentric angle of P and e be the eccentricity of the ellipse, then sinθ =