Writing and using your own functions in Mathematica

This screencast demonstrates how to write simple functions in Mathematica and how compute values from them, differentiate them, and plot them.

[carlchen]

Thanks, watching a real time demo makes it so easy to understand!!

[The_NASA_GUY]

I like your style. You should definitely do more examples of user-defined functions.

[sumsw]

Great example and well explained. Thank you. I do not have mathematica yet, but I am seriously considering the investment. One question if I may:
Can I define z[t_] :=t^ + 1 then define
p[x_, t_, z_ ]:= t^2 + 5x + z where z is the function above?
Also, if I take the first derivative with respect to t I prefer to see 2t = dZ/dt
Is that possible?

[sagarvinayak]

Hello sir, thanks for wonderful lessons. I have a doubt that (Can we evaluate a polynomial suppose x^2+x+1 at values 0, 1, 2, ...., 25 in a single command?) If it is possible then please let me know.

[asmaesaadi]

if a have a variable x in a function (f(x)=x+1) how I can write in mathematica this variable x in terms of the function itself x=f(x)-1 automatically in mathematica

[aatmangoti]

Please explain f[1] is possible
Yes or not

[brandomiranda]

sorry if you mentioned this somewhere, but why do we need the underscore to the argument of the function?

[emilioluburic]

Paper in front of eyes and you are in element like Albert Einstein.Nose, hair forget code, I will explain this, N is natural numbers in formula not drugs.