# Letters in expressions and formulas

by Grog85
Tags: expressions, formulas, letters
 P: 2 Hello, first post for me so I am sorry if this is in the wrong topic. I'm am from the UK studying A-Level Physics. I understand some formulas but this is testing me. Before I message my tutor I thought I would try here. Looks like a very useful website. Letters in expressions and formulas. v2 = u2 + 2as I normally understand maths when I know the rules. 2 × 5 is written as 2 × 5 or 10 2 × a is written as 2a a × b is written as ab I don't seem to understand this and I can't seem to find helpful information and I will not skip the page. Sorry if this is in the wrong topic and thank you for your help.
PF Gold
P: 1,355
 Quote by Grog85 v2 = u2 + 2as
Do you mean ##u^2## and ##v^2##, with the 2 small and high? In that case, it is called an exponent and, in the present case, means "squared":
$$u^2 = u \times u$$
and
$$v^5 = v \times v \times v \times v \times v$$
You can have a look at Wikipedia for what it means when the exponent is not a positive integer.
 HW Helper P: 3,540 Multiplication is used so much in maths that it's simply much easier to get rid of the $\times$ symbol. This also meant that the letter $x$ could be used as a variable (and it's used a lot) without running into problems of ambiguity between it being a variable or a multiplication symbol. Whenever you have a situation like $2\times 5$ then you're expected to evaluate that to 10, while $2\times a=2a$ cannot be simplified further so it's ok to leave as it is. Other than that, I don't see what's so confusing about the notation.
P: 2
Letters in expressions and formulas

 Quote by DrClaude Do you mean ##u^2## and ##v^2##, with the 2 small and high? In that case, it is called an exponent and, in the present case, means "squared":
Yes, small 2 above the u.

Thank you for your help. I'll see how I get on.
 Emeritus Sci Advisor HW Helper Thanks PF Gold P: 6,554 You must have missed a couple of days in algebra class.
 Mentor P: 21,311 Grog85, if you're going to be studying physics, you'll need to get the algebra difficulties squared away first.
 P: 413 Grog85, there a site here that covers all the A-level maths topics: http://www.examsolutions.net/

 Related Discussions Chemistry 3 Precalculus Mathematics Homework 2 General Discussion 1 Calculus & Beyond Homework 2 Academic Guidance 2