1.

Find the area of the region bounded by the latus recta of the ellipse `x^2/a^2+y^2/b^2=1` and the targets to the ellipse drawn at their ends

Answer» equation of tangent PR
`(xx_1)/a^2+(yy_1)/b^2=1`
putting the extreme values
`(xe)/a+y/a`=1 -(1)
equation of tangent QR
`(xe)/a-y/b=1` -(2)
adding 1 and 2
`(2xe)/a=2`
`x=a/e`
putting this value in equation 1
`(xe)/a+y/a=1`
`a/e*e/a+y/a=1`
y=0
we got point R(`a/e`,0)
area of `triangle` PQR
A=`1/2*PQ*FR`
`A=1/2*(2b^2)/a*sqrt(a/e-ae)`
`A=1/2*(2b^2)/a*sqrt(a(1/e-e)`
`A=b^2/asqrt(a((1-e^2)/e)`
`A=b^2/asqrt(b^2/(ae))`
`A=b^2/asqrt(b^2/sqrt(a^2-b^2)`
`a=b^3/(a(a^2-b^2)^(1/4)`


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