Answer:
![\[x^{(1)/(4)}\]](https://img.qammunity.org/2021/formulas/mathematics/high-school/t770pfqv9utc52uoxj65t1hk0x7mt2x17m.png)
Explanation:
x is a variable which has been declared of type double.
Then square root of x can be expressed as
![\[√(x)\]](https://img.qammunity.org/2021/formulas/mathematics/high-school/xeqbtld7hsy7a4k9rydfovr8mkrnwip1zk.png)
The quartic root of a number is the square root of its square root.
In other words, quartic root of x can be expressed as
![\[\sqrt{√(x)}\]](https://img.qammunity.org/2021/formulas/mathematics/high-school/r483actj6on515kz2d3rla6ff2najxk7bb.png)
This can be expressed equivalently as
![\[\sqrt{x^{(1)/(2)}}\]](https://img.qammunity.org/2021/formulas/mathematics/high-school/zpuqz9g1u6upgjno8yt7aghraq3aoxxmq2.png)
![\[={x^{(1)/(4)}}\]](https://img.qammunity.org/2021/formulas/mathematics/high-school/qi0a4ao5tsy3ya279rlo8xsp1bwm7obgcp.png)