With WolframAlpha if I put 4/3*x^2+y^2+x*y/2-7*x-8*y-32=0 and click [Properties] I have: ellipse foci | (4.32758, -0.902184) | (-0.393151, 7.91858) vertices | (5.65532, -3.38309) | (-1.72089, 10.3995) center | (1.96721, 3.5082) semimajor axis length | 7.81613 semiminor axis length | 6.00576 area | 147.472 perimeter | 43.6092 focal parameter | 7.21054 eccentricity | 0.639994 I can get more detailed information using focus 4/3*x^2+y^2+x*y/2-7*x-8*y-32=0 I can go with the mouse under the box and click [A Plaintext] to better copy the values. But for the (strange) function E I must use "EllipticE". What I can get for "perimeter": Instead of -(48 sqrt(807/(14 + sqrt(13))) E(2/183 (-13 + 14 sqrt(13))))/(sqrt(13) - 14) I must use: -(48 sqrt(807/(14 + sqrt(13))) EllipticE(2/183 (-13 + 14 sqrt(13))))/(sqrt(13) - 14) I obtain: 43.60916678922859604926097900650864774629354110674636419999...