JEE Main2014MathematicsCircleActual
Let L ₁ be the length of the common chord of the curves x^2+y^2=9 and y^2=8 x , and L₂ be the length of the latus rectum of y^2=8 x , then:
Options
- AL ₁> L ₂
- BL ₁= L ₂
- CL ₁ < L ₂
- DL ₁ ~L ₂ = 2
Correct answer
C. L ₁ < L ₂
Step-by-step solution
We have aligned &x^2+(8 x)=9 &x^2+9 x-x-9=0 &x(x+9)-1(x+9)=0 &(x+9)(x-1)=0 &x=-9,1 & for x=1, y= 2 2 x = 2 2 & ~L ₁= Length of AB & = (2 2 +2 2 )^2+(1-1)^2 =4 2 & ~L ₂= Length of latus rectum &=4 a=4 2=8 & ~L ₁ < L ₂ aligned