Answer 1

I’ve done this in JavaScript, if you look at the code you should be able to understand the logic behind it and translate it to C++: https://replit.com/@MattDESTROYER/Trigonometric-Functions-Sine-Cosine-Tangent?v=1#index.js

The important part is this:
```
// subtract n^num/!num
result -= Math.pow(n, num) / factorialOf(num);
// increment num
num += 2;
// add n^num/!num
result += Math.pow(n, num) / factorialOf(num);
// increment num
num += 2;
// since we add and subtract we are effectively doubling the accuracy so instead of decrementing accuracy by 1, we decrement by 2
accuracy -= 2;
```
To be clear, you cannot simply calculate the sine of a number, you can approximate it using a series which gradually gets closer and closer to the exact value.