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# help

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$$A number x is 3 larger than its reciprocal. What is the value of \left(x-\frac{1}{x}\right)^4?$$

May 31, 2022

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to take the reciprocal of a number you raise it to the power of negative one, or divide 1 by the number (same thing)

so the reciprocal of x would be x^(-1), or just 1/x. we know that a number is 3 larger than its reciprocal, lets call this number x.

so 1/x <-- the reciprocal, plus 3 would be equal to x. we can write this as 1/x + 3 = x

lets add 1/x and 3, and we get (3x+1)/x = x

multiply both sides by x, and we get 3x+1 = x^2

now lets move this into a quadratic that equals zero

x^2-3x-1 = 0

we can use the quadratic formula to find x, and we end up with

x= (3 plusorminus sqrt(13))/2

now plug these values into (x-(1/x))^4

May 31, 2022