# How you do cubic? $\pm$

Given that $s$ and $t$ equals

and $p$ and $q$ such that

Manipulating a little bit, $T$ should become

See how $T$ and $S$ have a $\pm$ in them? When you subtract $s$ from $t$, why does that $\pm$ disappear, and does it equal to the same value as when they have the $\pm$ sign in them?

If you want to see this website, it is: Deriving the Cubic Formula

Note by Bloons Qoth
3 years, 2 months ago

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Yup, a simpler way to prove that cubic formula is to first depress the cubic polynomial. Cardano's method shows a good illustration of this.

- 3 years, 2 months ago

Do you see the last 2 pictures? I was wondering what method allows you to get rid of that $\pm$ sign.

- 3 years, 2 months ago