keep from evaluating a symbolic expression

Utter noob question but Im trying to build up a function and see it in with nice formatting in live script how do I keep it from evaluating?

Say below I want to make sure that I have typed it in correctly not auto evaluate it . Also is there anyway to use e as asymbol and not have it automatically evaluate it into its fractional form? Sorry for how basic this is Im sadly only on hour number 3 of this langauge .

4*pi^2 * (2*pi*100)^2 *1/5

[Abhijeet]

Hi, Chad

In the sentence "Also is there anyway to use e as asymbol", here 'e' is an exponential constant?

[Walter Roberson]

Pi = sym(pi);
E = exp(sym(1));
4*Pi^2 * (2*E*100)^2 * 1/5

ans = 

Answer 1

[Abhijeet]

Hi, Chad

I understand you want to visualize the expression without it getting evaluated.

This can be achieved using symbolic variables, but still, constants will be evaluated to a simplified expression.

Create ‘pi’ as a symbolic variable as demonstrated below:

Use 'e' as a symbolic variable to represent ‘e’ as an exponent constant without it getting evaluated.

Here is a demonstration to create symbolic variables:

For more insights on symbolic variables, kindly visit the below mentioned hyperlinks:

Symbolic Math Toolbox - MATLAB (mathworks.com)

What are symbolic variables? - (mathworks.com)

why use symbolic variables over others - (mathworks.com)

Choose Numeric or Symbolic Arithmetic - MATLAB & Simulink - MathWorks India

[Walter Roberson]

There was a long period during which

syms pi

would make pi into a symbolic variable that referred to the transcendental constant π. However, that is no longer the case; now syms pi makes pi into an ordinary variable that does not refer to the constant (the situation is a little stranger than that internally.)

These days, to get LiveScript to display π for values that refer to the transcendental constant, use

pi = sym(pi);

or do like I did, of using Pi for that purpose instead, so that the numeric pi remains accessible.

See the difference:

syms pi
vpa(pi)

ans = 

π

clear pi
pi = sym(pi)

pi = 

π

vpa(pi)

ans = 

3.1415926535897932384626433832795

[Chad]

Awesome , thanks for yalls help

Answer 2

[Walter Roberson]

You can use displayFormula on the character (or string()) version of the formula, and later convert that to symbolic

as_char = '4*pi^2 * (2*pi*100)^2 *1/5'

as_char = '4*pi^2 * (2*pi*100)^2 *1/5'

displayFormula(as_char)

as_sym = str2sym(as_char)

as_sym =