There are many backstabbing rivalries in the history of the world. A 16th-century conflict between Italian mathematicians Gerolamo Cardano, a brilliant but troubled polymath, and Niccol Fontana, better known as Tartaglia, was dramatic. There is a central issue in the equation.

The quadratic formula is used by most high school students. The solutions of $latexax2+bx+c=0$ are stated.

frac -bpmsqrtb2-4ac2a

Is there a formula for an equation with a bigger power of x? The task of determining this was done before Cardano and their peers.

The 17th century was when modern algebra as we know it was first developed. Over the past thousand years, the ability to solve linear and quadratic equations has been developed.

In the 16th century, all coefficients had to be non negative since mathematicians didn't recognize negative numbers as legitimate. Without the idea of an unknown variable x, the equation of a cube and a number was referred to as a cube and a number. It was seen as more than a dozen separate problems, with the terms on one or the other side of the equal sign, when it was first thought of.

Modern symbolic algebra is important for mathematicians. It is possible to see the expression $latex(a+b)2=a2+2ab+b2$ as saying that the area of a square of side-length $latexa+b$ is the same as the area of a square of side-

Squares showing an equality between quadratic expressions

There is a cube decomposing into six boxes.

As long as the text is legible.

Cubes showing an equality between cubic expressions

A professor at the University of Bologna in the early 16th century,Scipione del ferro, was the first to make significant headway into the field of solved equations. Thanks to a curious culture of academic secrecy, we don't know all his accomplishments. Scholars would challenge each other to mathematical duels instead of racing to publish their work and be recognized for their work. The one who solved the most challenges was the winner. Professional advancement and more students are what the victors get. Secret weapons would be used in future contests.

When c and d are positive, it's possible for del ferro to solve equations of the form $latexx3+cx This one is called a "depressed cubic." No mathematician in the 16th century would express it this way.

del ferro's solution did not apply to other depressed cubics because the equations with different signs on the coefficients were considered different problems Antonio Fior bragged that he could solve these equations after del ferro died.

The self-taught Tartaglia found a way to solve a different form of the cubic. The stage was set for a mathematical battle between the two people. They had a deadline of a month and a half. The weaker of the two teams used the "all eggs in one basket" strategy and sent a lot of problems. After figuring out how to solve them, Tartaglia finished them all in two hours. He didn't solve any of his problems. The news spread throughout Italy of the accomplishment.

The process of discovery is explored in this column. David S. Richeson is a professor of mathematics.

You can see all the columns that have been quantized.

The prevailing wisdom was that it was not possible. Cardano was a cantankerous doctor who was beset by trouble after trouble. He struggled with his sons and was jailed during the Inquisition. He made contributions in medicine, philosophy, music, and physics. Cardano was a great man with all his flaws, but without them, he would have been incomparable, according to the author. The first serious investigations of probability theory are included in his collection of works.

Cardano tried and failed to duplicate Tartaglia's success with the cubic, so he began a pressure campaign to convince him to share his method.

I swear to you by the Sacred Gospel, and on my faith as a gentleman, not only never to publish your discoveries, if you tell them to me, but I also promise and pledge my faith as a true Christian to put them down in cipher so that after my death no one shall be able to understand them.

In 1539, Tartaglia relented and shared his techniques for depression with Cardano, but he didn't give proof that it worked. The underlying mathematics were discovered by just knowing the method. Cardano was able to solve any depression. He noticed that substituting was something that was done.

t fracb3a

A depressed cubic with variable t can be found with the help of $latexax3+bx2+cx+d=0$. He could find x if he plugged the equation back into the substitution formula. Every equation was solved by Cardano.

Cardano taught his assistant how to do these things. Although he was Cardano's servant, he became Cardano's equal. Cardano found a way to reduce any quartic equation to a cubic by helping him with his work. Any equation of degree four or less can be solved by Cardano andFerrari.

The results were important to Cardano and he wanted to publish them. It would be against his oath to do so since they all sprouted from the seeds he planted.

Cardano saw in del ferro's notebooks that he had solved the depressed cubic before Tartaglia. Cardano thought that this discovery freed him of his obligation. Ars Magna was published two years after Cardano did.

Cardano acknowledged his work in the book, but that didn't make Tartaglia happy. Cardano was accused of stealing and breaking a vow. The rebukes were given to Cardano's dog. The acrimonious back-and-forth, in the form of public pamphlets, continued for many months, leading to a mathematical battle between the two men. The esteemed Cardano refused to battle Tartaglia. The debate went badly for Tartaglia, especially with the rowdy crowd. The next day, when the debate was to continue, he was nowhere to be found.

It was ruined by the job offers that were flooding in. Cardano achieved immortality despite many notable accomplishments beyond those related to the cubic. Ars Magna is believed to be the start of modern mathematics.

The mathematicians were wondering how high they could go. It wasn't very far.

It is not possible to express the roots of the quintic equations in degree 5. The exact value can't be expressed with those tools because the root is so small.

The first proof of this fact was given in 1824. In 1830, the 18-year-old political firebrand variste Galois gave exact criteria for when a polynomial of any degree is solvable. His contributions to mathematics were large even after he died in a gun battle.

They were not the end of the story. polynomials and their roots are studied by mathematicians. David Hilbert proposed a problem in 1900 about the roots of seventh- degree polynomials. It was thought to have been solved in the 1950's, but is now the subject of renewed interest. Modern mathematicians can make headway on the problem if they don't create a rivalry around it.