Quant concept - Functions

So after so many days, i am writing about functions. Iwas too busy so just could not post the next posts. So here we go again..
Here are some very very important points about functions. I am starting with basics now..
1) Functions will always be in a form of
y=f(x)
equation will always be in a form of
f(x)= 0

2) when y=f(x)
x= independant variable
y= dependant variable

3) What is Domain of a function?
Domain is a set of values for viz equation make sense.
e.g y=x^2
so D = x>0 (i.e. x should not be zero in order to validate the equation, else if x=0 then y=0 and indirectly equation will be zero)

4) What are even functions?

f(x)=f(-x) then function is said to be even function

Some important points about function-->
1)Sum, difference,product,quotient of an even function is even
2)Graph of even function wil be always symmetrical about "y-axis" when x is independane variable and y is dependant varibale.
When this condition changes, then graph wil be symmeterical about "x-axis".
5) What are odd functions?
when f(x)= -f(-x) then function would called as od function

some important points for odd function -->
1) Sunm & difference of odd function is odd.
2)roduct & quotient is even.
3)The graph of odd function is always symmetrical about "Origin".

For now i am ending this post here as i need to go home and have a dinner. I will update this function tomorrow again with more concepts about functions.

I hope this helps to many people..

Enjoy & good night & sweet dreams :)

Regards,
Ameya