I'm reading a formula (lots of greek letters) and I see a symbol that looks like a backward six. That doesn't seem to be any greek letter... What is it?
You seem to be describing the nameless "partial derivative" symbol, sometimes called "del", a modified lower case Greek delta.
See
http://en.wikipedia.org/wiki/Partial_derivative
Ah ha! That's exactly what that is. And I knew that a long time ago. Thanks!
It doesn't show up on Wikipedia's greek alphabet page at all, but that's more than good enough! Thanks!
The symbol you are referring to is most likely the mathematical symbol called "capital sigma" or "sum symbol," which looks like a backward letter "E" (∑). It is not a Greek letter, but it is widely used in mathematics to represent a sum or summation.
The capital sigma symbol (∑) signifies that you need to sum up a series of terms. It is commonly used in algebra, calculus, and statistics. When you encounter this symbol, there is usually an expression or equation written below it, indicating the pattern of terms to be summed. The index of summation is often written above and below the sigma symbol, indicating the starting and ending points of the summation.
To evaluate the summation, you can follow these steps:
1. Identify the range of values over which you want to sum the terms. The index of summation typically provides this information.
2. Replace the index of summation with the initial value and calculate the resulting expression.
3. Increase the index value by one and repeat the evaluation until you reach the final value.
4. Sum up all the calculated values to obtain the final result.
It's important to note that the expression being summed can vary, ranging from simple numbers to more complex mathematical formulas or sequences.
Example:
If you have a summation expression with the capital sigma (∑) symbol, say ∑(2i), where i starts from 1 to 5, you would evaluate it as follows:
∑(2i) = 2(1) + 2(2) + 2(3) + 2(4) + 2(5)
= 2 + 4 + 6 + 8 + 10
= 30
So, in this example, the final result of the summation is 30.