Question 893725
An ellipse with horizontal major axis, center at (4,3), its major axis is twice as long as its minor axis, passes through P(2,1). Find its equation.
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Standard form of equation for an ellipse with horizontal major axis: 
{{{(x-h)^2/a^2+(y-k)^2/b^2=1}}}, a>b, (h,k)=coordinates of center
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given center: (4,3)
a=2b
{{{(2-4)^2/(2b)^2+(1-3)^2/b^2=1}}}
{{{(-2)^2/(2b)^2+(-2)^2/b^2=1}}}
{{{4/4b^2+4/b^2=1}}}
{{{1/b^2+4/b^2=1}}}
5/b^2=1
b^2=5
b=√5
a=2b=2√5
a^2=20
Equation: {{{(x-4)^2/20+(y-3)^2/5=1}}}