system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What math is being done when you press tan, cos or sin into a calculator?
gpt
Fun fact!  Crazy looking functions can be broken down into a series of relatively simply math problems that, if you add them all together, you get the crazy function.  It's called the Taylor series of that function.  

To calculate the sine of a number, take the number x, subtract x^3 / (3x2x1), add x^5 / (5x4x3x2x1), subtract x^7 / (7x6x5x4x3x2x1), and repeat that pattern.  It will get closer and closer to the actual value of sin(x).  Calculators will do this, and stop when the answer is close enough for the calculator.  Similar series exist for cos, tangent e^x, and others.