What is the definition for an EXPRESSION ?
An expression in English can be a short sentence, or a sentence fragment.
Take a hike. Go figure. What's up? Whatever.
In math, an expression is again a fragment, it can be complete or not complete.
2x + 1
Sin^2(2x) + 2
e^(2x + cosTheta)
19+42x + 2.3y
all are expressions. The dictionary defines (math) expression as a group of symbols that make a mathematical statement
My math teacher asked for the weather of dates as they passed so we could make a graph well I need to know some tempertures of the dates I need
Anonymous gave a very good explanation in my opinion.
Generally we separate expressions from equations. For equations we typically want to solve one variable in terms of one or more other variables or constants. For expressions we are typically interested in showing different ways it can be written or simplified. Some textbook writers might use the terms interchangably, but many use them the way explained above.
9+1=