The perfect square
Let's highlight the perfect square of the square three-member
$$\left(4 x^{4} - x^{2}\right) + 2$$
To do this, let's use the formula
$$a x^{4} + b x^{2} + c = a \left(m + x^{2}\right)^{2} + n$$
where
$$m = \frac{b}{2 a}$$
$$n = \frac{4 a c - b^{2}}{4 a}$$
In this case
$$a = 4$$
$$b = -1$$
$$c = 2$$
Then
$$m = - \frac{1}{8}$$
$$n = \frac{31}{16}$$
So,
$$4 \left(x^{2} - \frac{1}{8}\right)^{2} + \frac{31}{16}$$
/ / / ____\\ / / ____\\\ / / / ____\\ / / ____\\\ / / / ____\\ / / ____\\\ / / / ____\\ / / ____\\\
| 3/4 |atan\\/ 31 /| 3/4 |atan\\/ 31 /|| | 3/4 |atan\\/ 31 /| 3/4 |atan\\/ 31 /|| | 3/4 |atan\\/ 31 /| 3/4 |atan\\/ 31 /|| | 3/4 |atan\\/ 31 /| 3/4 |atan\\/ 31 /||
| 2 *cos|------------| I*2 *sin|------------|| | 2 *cos|------------| I*2 *sin|------------|| | 2 *cos|------------| I*2 *sin|------------|| | 2 *cos|------------| I*2 *sin|------------||
| \ 2 / \ 2 /| | \ 2 / \ 2 /| | \ 2 / \ 2 /| | \ 2 / \ 2 /|
|x + ---------------------- + ------------------------|*|x + ---------------------- - ------------------------|*|x + - ---------------------- + ------------------------|*|x + - ---------------------- - ------------------------|
\ 2 2 / \ 2 2 / \ 2 2 / \ 2 2 /
$$\left(x + \left(\frac{2^{\frac{3}{4}} \cos{\left(\frac{\operatorname{atan}{\left(\sqrt{31} \right)}}{2} \right)}}{2} - \frac{2^{\frac{3}{4}} i \sin{\left(\frac{\operatorname{atan}{\left(\sqrt{31} \right)}}{2} \right)}}{2}\right)\right) \left(x + \left(\frac{2^{\frac{3}{4}} \cos{\left(\frac{\operatorname{atan}{\left(\sqrt{31} \right)}}{2} \right)}}{2} + \frac{2^{\frac{3}{4}} i \sin{\left(\frac{\operatorname{atan}{\left(\sqrt{31} \right)}}{2} \right)}}{2}\right)\right) \left(x + \left(- \frac{2^{\frac{3}{4}} \cos{\left(\frac{\operatorname{atan}{\left(\sqrt{31} \right)}}{2} \right)}}{2} + \frac{2^{\frac{3}{4}} i \sin{\left(\frac{\operatorname{atan}{\left(\sqrt{31} \right)}}{2} \right)}}{2}\right)\right) \left(x + \left(- \frac{2^{\frac{3}{4}} \cos{\left(\frac{\operatorname{atan}{\left(\sqrt{31} \right)}}{2} \right)}}{2} - \frac{2^{\frac{3}{4}} i \sin{\left(\frac{\operatorname{atan}{\left(\sqrt{31} \right)}}{2} \right)}}{2}\right)\right)$$
(((x + 2^(3/4)*cos(atan(sqrt(31))/2)/2 + i*2^(3/4)*sin(atan(sqrt(31))/2)/2)*(x + 2^(3/4)*cos(atan(sqrt(31))/2)/2 - i*2^(3/4)*sin(atan(sqrt(31))/2)/2))*(x - 2^(3/4)*cos(atan(sqrt(31))/2)/2 + i*2^(3/4)*sin(atan(sqrt(31))/2)/2))*(x - 2^(3/4)*cos(atan(sqrt(31))/2)/2 - i*2^(3/4)*sin(atan(sqrt(31))/2)/2)