title: The user input for a calculating the tangent of a graph
body: <p>I am making a program that calculates the equation for the tangent of a graph at a given point and ideally I'd want it to work for any type of graph. e.g. 1/x ,x^2 ,ln(x), e^x, sin, tan. I know how to work out the tangent and everything but I just don't really know how to get the input from the user.</p>
  
  <p>Would I have to have options where they choose the type of graph and then fill in the coefficients for it e.g. "Choice 1: 1/(Ax^B) Enter the values of A and B"? Or is there a way so that the program recognises what the user types in so that instead of entering a choice and then the values of A and B, the user can type "1/3x^2" and the program would recognise that the A and B are 3 and 2 and that the graph is a 1/x graph.</p>
  
  <p>This website is kind of an example of what I would like to do be able to do: <a href="https://www.symbolab.com/solver/tangent-line-calculator" rel="nofollow noreferrer">https://www.symbolab.com/solver/tangent-line-calculator</a></p>
  
  <p>Thanks for any help :)</p>