椭圆x^2/a^2+y^2/b^2=1(a大于b大于0)的左右焦点为F1F2若角pf1f2=75度,角PF2F1=15度则b/a=

问题描述:

椭圆x^2/a^2+y^2/b^2=1(a大于b大于0)的左右焦点为F1F2若角pf1f2=75度,角PF2F1=15度则b/a=