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Find the points on the ellipse 4x2 + y2 = 4 that are farthest away from point (1, 0)
Solution:
Given, equation of ellipse is 4x2 + y2 = 4
We have to find the points on the ellipse that are farthest away from the point (1, 0)
Consider (x,y) as the point on the ellipse 4x2 + y2 = 4
We can write it as,
y2 = 4 - 4x2 --- (1)
Taking square root,
y = \(\pm 2\sqrt{1-x^{2}}\)
Distance between (x, y) and (1, 0) is
d(x) = \(\sqrt{(x-1)^{2}+y^{^{2}}}\)
Substituting the value of y²,
d(x) = \(\sqrt{(x-1)^{2}+4-4x^{2}}\)
On simplification,
d(x) = \(\sqrt{x^{2}+1-2x+4-4x^{2}}\)
d(x) = \(\sqrt{-3x^{2}-2x+5}\)
Now we have to maximize f(x)
f(x) = \(\sqrt{-3x^{2}-2x+5}\)
f’(x) = -6x - 2
To find critical value,f’(x) = 0
-6x - 2 = 0
-6x = 2
x = -2/6
x = -1/3
Now, f’’(x) = -6
Where x=-1/3 which maximizes f(x) and d(x)
\(y=\pm 2\sqrt{1-(\frac{-1}{3})^{2}}\)
\(y=\pm 2\sqrt{1-(1/9)}\\y=\pm 2\sqrt{\frac{8}{9}}\)
\(y=\pm \frac{2(2\sqrt{2})}{3}\)
\(y=\pm \frac{4\sqrt{2}}{3}\)
Therefore, the farthest points away from the point (1, 0) are (-1/3 , \(y=\pm \frac{4\sqrt{2}}{3}\))
Find the points on the ellipse 4x2 + y2 = 4 that are farthest away from point (1, 0)
Summary:
The points on the ellipse 4x2 + y2 = 4 that are farthest away from the point (1, 0) are (-1/3, \(y=\pm \frac{4\sqrt{2}}{3}\))
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