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Find length of latus rectum and eccentricity of ellipse |
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Answer» The given equation is \displaystyle 16x^{2}+y^{2}= 1616x 2 +y 2 =16 It can be written as \displaystyle 16x^{2}+y^{2}= 1616x 2 +y 2 =16 \displaystyle \frac{x^{2}}{1}+\frac{y^{2}}{16}= 1 1 x 2
+ 16 y 2
=1 \displaystyle \frac{x^{2}}{1^{2}}+\frac{y^{2}}{4^{2}}= 1 ...(1) 1 2
x 2
+ 4 2
y 2
=1...(1) Herethe denominator of \displaystyle \frac{y^{2}}{4^{2}} 4 2
y 2
is greater than the denominator of \displaystyle \frac{x^{2}}{1^{2}} 1 2
x 2
Therefore, the major axis is along the yy-axis while the minor axis is along the xx-axis. On comparing equation (1) with \displaystyle \frac{x^{2}}{B^{2}}+\frac{y^{2}}{a^{2}}= 1 b 2
x 2
+ a 2
y 2
=1, we obtain b = 1b=1 and a = 4a=4 \displaystyle \therefore ae=c = \sqrt{a^{2}-b^{2}}=\sqrt{16 - 1}=\sqrt{15}∴ae=c= a 2 −b 2
= 16−1
= 15
Therefore, the coordinates of the foci are \displaystyle \left ( 0, \pm \sqrt{15} \right )(0,± 15
) The coordinates of the VERTICES are \displaystyle \left ( 0, \pm 4 \right )(0,± 4) LENGTH of major axis = 2a = 8=2a=8 Length of minor axis = 2b = 2=2b=2 Eccentricity e =e= \displaystyle \frac{c}{a}=\frac{\sqrt{15}}{4} a c
= 4 15
Length of latus rectum == \displaystyle \frac{2b^{2}}{a}=\frac{2\times 1}{4}=\frac{1}{2} a 2b 2
= 4 2×1
= 2 1
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