Creearea funcțiilor în Mathematica

În Mathematica, o funcție se poate defini astfel:

f[x_]:=x^2+2x-4

In[3]:= f[1]
Out[3]= -1

In[4]:= f[π]
Out[4]= -4+2π+π2

<comments> $d_{\text{F}}=\frac{2D^2}{\lambda }$ </comments>

You can define your own function in Mathematica like this (use the Basic Math Assistant palette to type x2; see Section 1.6):

Follow these rules when defining a function: $ The name of the function (such as f or inv) should be a lowercase letter, or a word that begins with a lowercase letter. This is because all built-in functions (such as Log and N) begin with capital letters. If your function begins with a lowercase letter, you will never accidentally give it a name that already belongs to some built-in function. $ The function argument (in these examples x) must be followed by an underscore _ on the left side of the definition. $ Use square brackets [ ] to enclose the function argument. $ Use the colon-equal combination := to separate the left side of the definition from the right.