So, I teach high school math and we use numworks graphing calculators. They've been excellent! However, I recently ran across an issue that shows you can't always trust what your calculator says.

Suppose you want to take the cube root of negative 230. You should get approximately -6.127. It is perfectly fine to take the cube root of a negative number and get a real result. However, if the calculator is in Complex/Cartesian mode for displaying complex numbers, you get approximately 3.063+0.306i. Simply moving the negative sign outside of the radical sign (again, this is just fine to do in high school), you get the correct answer as shown below.

I wonder what causes this?

#math #HighSchool #teaching #calculator #numworks #radicals

So, I teach high school math and we use numworks graphing calculators. They've been excellent! However, I recently ran across an issue that shows you can't always trust what your calculator says.

Suppose you want to take the cube root of negative 230. You should get approximately -6.127. It is perfectly fine to take the cube root of a negative number and get a real result. However, if the calculator is in Complex/Cartesian mode for displaying complex numbers, you get approximately 3.063+0.306i. Simply moving the negative sign outside of the radical sign (again, this is just fine to do in high school), you get the correct answer as shown below.

I wonder what causes this?

#math #HighSchool #teaching #calculator #numworks #radicals