Mister Exam
Factor -y^4-y^2+8 squared
The solution
Factorization
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/ ____________\ / ____________\ / ______________\ / ______________\ | / ____ | | / ____ | | / ____ | | / ____ | | / 1 \/ 33 | | / 1 \/ 33 | | / 1 \/ 33 | | / 1 \/ 33 | |x + I* / - + ------ |*|x - I* / - + ------ |*|x + / - - + ------ |*|x - / - - + ------ | \ \/ 2 2 / \ \/ 2 2 / \ \/ 2 2 / \ \/ 2 2 /
$$\left(x - i \sqrt{\frac{1}{2} + \frac{\sqrt{33}}{2}}\right) \left(x + i \sqrt{\frac{1}{2} + \frac{\sqrt{33}}{2}}\right) \left(x + \sqrt{- \frac{1}{2} + \frac{\sqrt{33}}{2}}\right) \left(x - \sqrt{- \frac{1}{2} + \frac{\sqrt{33}}{2}}\right)$$
(((x + i*sqrt(1/2 + sqrt(33)/2))*(x - i*sqrt(1/2 + sqrt(33)/2)))*(x + sqrt(-1/2 + sqrt(33)/2)))*(x - sqrt(-1/2 + sqrt(33)/2))
The perfect square
Let's highlight the perfect square of the square three-member
$$\left(- y^{4} - y^{2}\right) + 8$$
To do this, let's use the formula
$$a y^{4} + b y^{2} + c = a \left(m + y^{2}\right)^{2} + n$$
where
$$m = \frac{b}{2 a}$$
$$n = \frac{4 a c - b^{2}}{4 a}$$
In this case
$$a = -1$$
$$b = -1$$
$$c = 8$$
Then
$$m = \frac{1}{2}$$
$$n = \frac{33}{4}$$
So,
$$\frac{33}{4} - \left(y^{2} + \frac{1}{2}\right)^{2}$$
$$\left(- y^{4} - y^{2}\right) + 8$$
To do this, let's use the formula
$$a y^{4} + b y^{2} + c = a \left(m + y^{2}\right)^{2} + n$$
where
$$m = \frac{b}{2 a}$$
$$n = \frac{4 a c - b^{2}}{4 a}$$
In this case
$$a = -1$$
$$b = -1$$
$$c = 8$$
Then
$$m = \frac{1}{2}$$
$$n = \frac{33}{4}$$
So,
$$\frac{33}{4} - \left(y^{2} + \frac{1}{2}\right)^{2}$$
Combining rational expressions
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2 / 2\ 8 + y *\-1 - y /
$$y^{2} \left(- y^{2} - 1\right) + 8$$
8 + y^2*(-1 - y^2)