The Math node part of what you're looking for is very straightforward:
An Value node allows you to set T. The math is built up one node at a time from left to right. It takes 8 math nodes, set to various math functions, to build up the full equation but it is the one you specified as you can see by following the titles of the panels.
The bit that differs depending on whether you want this for geometry nodes or shader nodes consists of how you generate the values for X and what you do with the result.
I have left out the 'what to do with it'; but on the far left I've shown how to generate the X values using a gradient texture in the a shader. The gradient will generate the values from 0 - 1 based on the texture coordinate. That feeds a mapping node which converts the value, in this case, from $-\pi$ to $\pi$ because the math trig nodes what their input in radians and I picked the range arbitarily.
One way to produce the X values in Geometry nodes is to use a Points node to drive a Set Position Node and to do math to calculate the position. If you need that I can add such an example.