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← JEE Main 2022 · 27 Jun · Shift 1
MathematicsSingle correct+4 / -1Question 13 of 90

JEE Main 2022 · 27 Jun · Shift 1, Mathematics question 13

Let the eccentricity of an ellipse x2a2+y2b2=1\dfrac{x^2}{a^2}+\dfrac{y^2}{b^2}=1, a>ba>b, be 14\dfrac14. If this ellipse passes through the point (−425,3)\left(-4\sqrt{\dfrac25},3\right), then a2+b2a^2+b^2 is equal to :

Choose one option
Answer and worked solution

Official answer: B

Eccentricity. b2=a2(1−116)=1516a2b^2=a^2\left(1-\frac1{16}\right)=\frac{15}{16}a^2.

Through the point. 32/5a2+9b2=325a2+485a2=16a2=1\dfrac{32/5}{a^2}+\dfrac9{b^2}=\dfrac{32}{5a^2}+\dfrac{48}{5a^2}=\dfrac{16}{a^2}=1, so a2=16a^2=16, b2=15b^2=15.

Sum 31.

(B)

Topics:Ellipse