Using the formula editor: Working with symbols
Working with symbolic expressions
Mathematical formulas consist of more than just numbers: usually there are symbols present. Think of variables, names of physical quantities, names of functions, etcetera. To enter a mathematical formula you can use a keyboard and/or the formula editor. The table below lists the most common mathematical symbols and the syntax for entering them.
| Symbol | Syntax | #\phantom{x}# Description |
| \(\cos(x)\) | cos(x) | #\phantom{x}# cosine of \(x\) |
| \(\sin(x)\) | sin(x) | #\phantom{x}# sine of \(x\) |
| \(\tan(x)\) | tan(x) | #\phantom{x}# tangent of \(x\) |
| \(\ln(x)\) | ln(x) | #\phantom{x}# natural logarithm of \(x\) |
| \(\log_{a}(x)\) | log(a,x) or log_a(x) | #\phantom{x}# logarithm of \(x\) with base \(a\) |
| \(x^y\) | x^y | #\phantom{x}# \(x\) to the power \(y\) |
| \(e^x\) | e^x or exp(x) | #\phantom{x}# \(e\)-power of \(x\), exponential function |
| \(\sqrt{x}\) | sqrt(x) or rt(x,2) | #\phantom{x}# square root of \(x\) |
| \(\sqrt[n]{x}\) | rt(x,n) | #\phantom{x}# \(n\)-th root of \(x\) |
| \(|x|\) | abs(x) | #\phantom{x}# absolute value of \(x\) |
| \(\displaystyle \frac{x}{y}\) | x/y | #\phantom{x}# \(x\) divided by \(y\) |
| \(x\cdot y\) | x*y | #\phantom{x}# product of \(x\) and \(y\) |
| \(\pi\) | pi | #\phantom{x}# the constant \(\pi\) |
There are a few things you should pay special attention to. The main rule is:
Almost always use the multiplication sign *
The only exception to the above rule is when an integer is followed by a letter or known symbol such as in \(2x\) and \(2\pi\).
xy is a name consisting of two characters; x*y is the product of two variables.
x2 is a name consisting of a letter followed by a number; x*2 is the product of a variabele and a number.
By the way, the system often warns its user when names consisting of two letter are entered:
Also in case of brackets it is often necessary to enter a multiplication symbol:
So not 2(x+1) and(x+1)x, but (x+1)*x to denote a factorized expression.
f(x-1) usually indicates a function call with argument x-1, but it can also be read as a product of f and x-1; in case of f*(x-1), there is no doubt anymore, because this is certainly a product.
