Symbol doubt

Sir,

In the Picture.,

Whats the meaning of that symbol (in the red box).?
What is the name of that symbol?
Explanation about the working way of that symbol?
Any websites(if any) suggest for more Detailed Information about that symbol?

This discussion board is a place to discuss our Daily Challenges and the math and science related to those challenges. Explanations are more than just a solution — they should explain the steps and thinking strategies that you used to obtain the solution. Comments should further the discussion of math and science.

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Markdown	Appears as
`italics` or `_italics_`	italics
`bold` or `__bold__`	bold
- bulleted - list	bulleted list
1. numbered 2. list	numbered list
Note: you must add a full line of space before and after lists for them to show up correctly
paragraph 1 paragraph 2	paragraph 1 paragraph 2
`[example link](https://brilliant.org)`	example link
`> This is a quote`	This is a quote
# I indented these lines # 4 spaces, and now they show # up as a code block. print "hello world"	# I indented these lines # 4 spaces, and now they show # up as a code block. print "hello world"

Math	Appears as
Remember to wrap math in `$` ... `$` or `\[` ... `\]` to ensure proper formatting.
`2 \times 3`	$2 \times 3$
`2^{34}`	$2^{34}$
`a_{i-1}`	$a_{i-1}$
`\frac{2}{3}`	$\frac{2}{3}$
`\sqrt{2}`	$\sqrt{2}$
`\sum_{i=1}^3`	$\sum_{i=1}^3$
`\sin \theta`	$\sin \theta$
`\boxed{123}`	$\boxed{123}$

Comments

A simple example: for all positive integers $k$ , $k!=1\cdot 2\cdot 3\cdot \ldots\cdot (k-1)\cdot k = \prod_{i=1}^k i.$

David Altizio - 8 years ago

As $\sum$ means addition, $\prod$ means product.

Vikram Waradpande - 8 years ago

Product symbol

Sona Priyadarshini - 8 years ago

we call it pie...it stands for continous product....

A Former Brilliant Member - 8 years ago

it is pie , it means cyclical multiplication , just multiply cyclicaly!

superman son - 8 years ago

ρ whatis standing for ut?

ahmed yahia - 8 years ago

pardon???

A Former Brilliant Member - 8 years ago

I think means what does $\rho$ stand for.

Vikram Waradpande - 8 years ago

Math	Appears as
Remember to wrap math in `\(` ... `\)` or `\[` ... `\]` to ensure proper formatting.
`2 \times 3`	$2 \times 3$
`2^{34}`	$2^{34}$
`a_{i-1}`	$a_{i-1}$
`\frac{2}{3}`	$\frac{2}{3}$
`\sqrt{2}`	$\sqrt{2}$
`\sum_{i=1}^3`	$\sum_{i=1}^3$
`\sin \theta`	$\sin \theta$
`\boxed{123}`	$\boxed{123}$