The nature of odd function
1, the difference between the sum or subtraction of two odd function is odd function.
2. The difference between the sum or subtraction of even and odd functions is the parity function.
3. The quotient obtained by multiplication or division of two odd function is an even function.
4. The quotient of the product or division of an even function multiplied by a odd function is odd function.
Properties of even function
1. If the function expression is known, f(x) = f (-x) is satisfied for any x in the domain of function f (x), for example, Y = X * X
2. If the image is known, the even function image is symmetric about y axis (straight line x=0).
3. The symmetry of region D about the origin is a necessary and sufficient condition for this function to become an even function.