# Math Help - inverted 6 symbol

1. ## inverted 6 symbol

can anyone enlighten me as to what the inverted 6 symbol means? its the number 6 inverted left to right. i came across it in my calculus notes under partial derivatives under functions of two variables.

the formula goes

fx = (inverted 6)f/(inverted6)x = (inverted 6)z/(inverted 6)x
fy = (inverted 6)f/(inverted6)y = (inverted 6)z/(inverted 6)y

they are defined by the limits:
(inverted 6)f/(inverted 6)x = lim (as h approaches 0) [f(x+hy)-f(xy)] /h

2. The formula is meant to answer your question! It's a definition just explaining the meaning of the notation, which makes the left and right sides just alternative notations - just as dy/dx and y' are alternatives. $\partial$ is just d for partial differentiation, in which all variables not selected by this symbol are held as constants during differentiation - and notice the latex code is \partial

3. Originally Posted by tom@ballooncalculus
The formula is meant to answer your question! It's a definition just explaining the meaning of the notation, which makes the left and right sides just alternative notations - just as dy/dx and y' are alternatives. $\partial$ is just d for partial differentiation - and notice the latex code is /partial
oh okay... sorry for my dumb question... never really paid attention in lectures so thought it was a symbol for something... thanks for explaining...

4. The 'dumb' questions are often the ones that need asking!

5. I once had a class of Junior and Senior math majors whose Advanced Calculus text book included the sentence:
"In this case we say that y is proportional to x: in symbols, $y \alpha x$."

Every one wanted to know what that symbol, $\alpha$ meant!