How to get servo angle to change based on a mathematical function

Using Arduino Motors, Mechanics, Power and CNC
3

Can you help me with this part?
I want my servo angle be [ arctan(5t/8.255) ] based on the variable of t (seconds)
I've been trying to declare different variable and even downloaded a couple libraries, but it's not working and I'm having problems.
This is the base code that I keep trying to get to work:

#include <Wire.h>
#include <Adafruit_MotorShield.h>
#include <Servo.h>
#include <math.h>
Adafruit_MotorShield AFMS = Adafruit_MotorShield();
Servo servo1;
Servo servo2;


void setup() {
  
Serial.begin(9600);
Serial.println("wrist");
AFMS.begin();


servo1.attach(10);
servo2.attach(9);
servo1.write(180);
servo2.write(0);
}

void loop() {
  {

 servo1.write(double  atan2 (double __y, double __x);
}}
}