This function is a piecewise function. If you want to prove that this function is odd function, you need to prove that X >；; 0 and x

1, when -x<；,-x <; 0 into -x? -2x-3。 have

f(-x)=-(-x)？ -2(-x)-3=-x？ +2x-3= -(x？ -2x+3)=-f(x)∴f(-x)=-f(x)；

2. when x

f(-x)=(-x)？ -2(-x)+3=x？ +2x+3= -( -x？ -2x-3)=-f(x) ∴ f(-x)=-f(x)

3 and f(0)=0.

∴ In the domain of f(x), there is f (-x) =-f(x). According to odd function's definition, f (x) is known as odd function. Complete the certificate.