Input function - bad argument value

[Amer7]

Hi,
Folks I have a problem, my tasks became to complicated for me to calculate it all by hand ( I don't have enough time to complete the task)

How can I input a function like:
a1=d1*cos(alpha)+X
a2=d1*sin(beta)+Y
a3=d2*cos(beta)
a4=d3*sin(beta) ....

I can have Xx amount of these functions

And then tell the program to derivation of functions by variable that in input.
like alpha, beta, d1, d2


As you can see these are stored in matrix
The issue is when I write the input program it doesn't let me input the function.
How can I make this on Prime?

1. Issue is how do I make first input screen to let me enter the numbers of how many inputs spaces I need.
2. How do I input the function