# How to enter the formula for calculating roots for a 2. degree polynomial in the CAS-view with +/- ?

Aritmometer shared this question 2 months ago

I would like to write the formula for calculating roots for a 2. degree polynomial in the CAS-view with +/- as I would like to get the students to manipulate it so that they in the end get; ax^2 + bx + c = 0.

How can I do that ?

And is it also possible to enter +/- in LaTex and if so how ? 1

+/- is no option to use as one sign (I mean of course in calculations). In fact it's always a simplification for the fact that there are two solutions. So you have te split up the two solutions while calculating, but of course you can use it in texts. 1

LaTeX :

- ± is \pm

- ∓ is \mp 1

why CAS?

type

a=2

b=3

c=4

a x^2+b x+c=0 (be careful with blank)

then drag and drop the selection square of polynomial to graphics window (selection square is at left of polynomial expression)

double click in text for editing

change the second parameter by false

and the formula text2 = "\frac{-b\pm \sqrt{b^{2}-4ac}}{2a}"