Take the 2-minute tour ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

When we multiply out $(x + y)(x + y)$, we refer to the two $xy$ terms as "cross terms". Is there a corresponding term for the $x^2$ and $y^2$ terms?

share|improve this question
    
I'm not aware of standard terminology, but I'd call them "pure terms". –  Matt Pressland Mar 28 '12 at 13:15
2  
The happy terms?! –  Ross Millikan Mar 28 '12 at 13:21
    
The "non-cross" terms? –  David Mitra Mar 28 '12 at 13:26

6 Answers 6

up vote 7 down vote accepted

Depending on the context, "diagonal terms" might work:

$$(x+y)(x+y)=\pmatrix{x&y}\pmatrix{1&1\\1&1}\pmatrix{x\\y}\;;$$

the cross-terms are the off-diagonal terms in this quadratic form and the other ones are the diagonal terms.

share|improve this answer
    
+1, Came here to give this answer. I think I have seen diagonal used most often. –  Eric Naslund Mar 28 '12 at 13:29

Direct or straight might be what you are looking for, as opposed to cross, crossed or mixed (since each resultant term has either one variable to a power or two different variables, a "mixture").

I was also taught that you can multiply $(a+b)(c+d)$ using the acronym FOIL for First, Inside, Outside, Last (which is mixing sequential and spatial metaphors).

share|improve this answer

The squares or more general, the $n$th power.

share|improve this answer

The aligned terms. ............

share|improve this answer

The square term or quadrature term is the best.

share|improve this answer

The univariate terms is unambiguous. I like 'pure' but am not sure how correct this is.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.