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Find the equation for the ellipse that satisfies the givenconditions:Major axis on the xaxis and passes through the points (4, 3) and(6, 2). |
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Answer» Since the major axis of the ellipse lies on the x-axis, so it is a horizontal ellipse. Let the required equation of the ellipse be `x^(2)/a^(2) +y^(2)/b^(2) = 1" "("where "a^(2) gt b^(2))." "` …(i) Since (4, 3) lies on (i), we have `16/a^(2) +9/b^(2) = 1." "` ...(ii) Also, since (6, 2) lies on (i) , we have `36/a^(2) + 4/b^(2) = 1." "`...(iii) Putting ` 1/a^(2) = u and 1/b^(2) = v ` in (ii) and (iii), we get `16u+9v=1" "`...(iv) `36u+4v=1" " ` ...(v) On multiplying (iv) by 9 and (v) by 4, and subtracting, we get ` 65v = 5 hArr v = 1/13 hArr 1/b^(2) = 1/13 hArr b^(2) = 13.` Putting ` v = 1/13 ` in (iv), we get ` 16 u = (1-9/13) hArr 16u = 4/13 hArr u = (4/13 xx 1/16) = 1/52 hArr 1/a^(2) = 1/52 hArr a^(2) = 52.` Thus, `a^(2) 52 and b^(2) = 13.` Hence, the required equation is `x^(2)/52 + y^(2)/13 = 1.` |
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