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Find the eccentricity, centre, vertices, foci,minor axis, major axis, directrices and latus-rectum of theellipse `25 x^2+9y^2-150 x-90 y+225=0.` |
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Answer» `x^2/a^2+y^2/b^2=1` `25x^2+9y^2-150x-90y+225=0` `25(x^2-6x)+9(y^2-10y)+225=0` `25(x^2-6x+9-9)+9(y^2-10y+25-25)+225=0` `25(x-3)^2-225+9(y-5)^2-225+225=0` `(25(x-3)^2)/225+(9(y-5))^2/225=1` `(x-3)^2/9+(y-5)^2/25=1` `x=X+3` `y=Y+5` `[x^2/3^2+Y^2/5^2=1]` `e=sqrt(1-a^2/b^2)=sqrt(1-9/25)=4/5` `x=0+3=3` `y=Y+5=Y+5=5+5=10` `y-5=5-5=0` `(3,0),(3,10)` `X=0,Y=pmbe` `x=X+3` `y=Y+5` `=-4+5=1` Equation of direction X and Y `Y=pmb/e=pm5/(4/6)=pm25/4` `y=Y+5=25/4+5=45/4` `y=445/4,y=-5/4` Major axis=`2b=2*5=10` Minor axis=`2a=2*3=6` Latus rectum=`(2a^2)/b=(2*9)/5=18/5` Length of latus rectum. |
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