if eccentric angle of a point lying in the first quadrant on the ellipse x^2/a^2+y^2/b^2=1 be theta and the line - Maths - Conic Sections

Question

if eccentric angle of a point lying in the first quadrant on the
ellipse x^2/a^2+y^2/b^2=1 be theta and the line joining the centre
to that point makes angle phi with the x axis, then (theta-phi)
will be maximum when theta=

Nikita Gupta · Answer

I got this answer below
<img src=
"https://s3mn%20mnimgs%20com/img/shared/content_ck_images/ck_5a0949821f655%20jpeg">

if eccentric angle of a point lying in the first quadrant on the ellipse x^2/a^2+y^2/b^2=1 be theta and the line joining the centre to that point makes angle phi with the x axis, then (theta-phi) will be maximum when theta=