Letters in expressions and formulas

  1. 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.
     
  2. jcsd
  3. DrClaude

    DrClaude 2,137
    Science Advisor
    Homework Helper

    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.
     
  4. Mentallic

    Mentallic 3,684
    Homework Helper

    Multiplication is used so much in maths that it's simply much easier to get rid of the [itex]\times[/itex] symbol. This also meant that the letter [itex]x[/itex] 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 [itex]2\times 5[/itex] then you're expected to evaluate that to 10, while [itex]2\times a=2a[/itex] 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.
     
  5. Yes, small 2 above the u.

    Thank you for your help. I'll see how I get on.
     
  6. SteamKing

    SteamKing 8,589
    Staff Emeritus
    Science Advisor
    Homework Helper

    You must have missed a couple of days in algebra class.
     
  7. Mark44

    Staff: Mentor

    Grog85, if you're going to be studying physics, you'll need to get the algebra difficulties squared away first.
     
  8. PeroK

    PeroK 1,083
    Homework Helper
    Gold Member

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