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Solve simultaneously: x^2+y^2=5 and 1/x^2+1/y^2=5/4​

User Jsol
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Answer:

We can start by rearranging the second equation as follows:

1/x^2 + 1/y^2 = 5/4

4/x^2 + 4/y^2 = 5

Multiplying both sides by x^2y^2, we get:

4y^2 + 4x^2 = 5x^2y^2

We can rearrange this equation as follows:

5x^2y^2 - 4x^2 - 4y^2 = 0

Using the quadratic formula, we can solve for xy:

xy = (4 ± sqrt(16 + 80))/10

xy = (4 ± 2sqrt(6))/10

xy = (2 ± sqrt(6))/5

Now we can use the fact that xy = (2 ± sqrt(6))/5 to solve for x and y. We can substitute y = (2 ± sqrt(6))/5x into the first equation:

x^2 + ((2 ± sqrt(6))/5x)^2 = 5

Expanding the square and simplifying, we get:

26x^4 - 50x^2 + 4 = 0

This is a quadratic equation in x^2, so we can use the quadratic formula to solve for x^2:

x^2 = (50 ± sqrt(50^2 - 4264))/52

x^2 = (25 ± sqrt(371))/26

Using the positive root for x^2, we can solve for x:

x = sqrt((25 + sqrt(371))/26) or x = -sqrt((25 + sqrt(371))/26)

Similarly, we can solve for y using the equation y = (2 ± sqrt(6))/5x:

y = (2 ± sqrt(6))/5 * sqrt((25 + sqrt(371))/26) or y = (2 ± sqrt(6))/5 * (-sqrt((25 + sqrt(371))/26))

Therefore, the solutions for x and y are:

x = sqrt((25 + sqrt(371))/26), y = (2 + sqrt(6))/5 * sqrt((25 + sqrt(371))/26)

OR

x = -sqrt((25 + sqrt(371))/26), y = (2 - sqrt(6))/5 * sqrt((25 + sqrt(371))/26)

Explanation:

User Emina
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