Question 35 of 106MediumNUMERICAL
Let the foci and length of the latus rectum of an ellipse \[\frac{x^2}{a^2}+\frac{y^2}{b^2}=1, a>b b e( \pm 5,0)\] and \[\sqrt{50}\]
Solutions · 1
Official solution
≡(±5,0);a2b2=50a=5b2=252ab2=a2(1−e2)=252a
⇒a(1−e2)=252⇒e5(1−e2)=252⇒2−2e2=e⇒2e2+e−2=0⇒2e2+2e−e−2=0⇒2e(e+2)−1(1+2)=0⇒(e+2)(2e−1)=0∴e=−2;e=21
b2x2−a2b2y2=1a=52b=5a2b2=b2(e21−1)⇒e21=51 Answer the question to unlock