Question 1199004
<pre>
A function is even when f(-x) = f(x) 
A function is odd when f(-x) = -f(x)

A) {{{"f(x)"=3x^3+5}}} 
{{{"f(-x)"=3(-x)^3 + 5 = 3(-x)(-x)(-x)+5 = -3x^3+5 <>"-f(x)"}}} <--not an odd function

B) {{{"f(x)"=x}}} 
{{{"f(-x)"=-x="-f(x)"}}} <--odd function

C) {{{"f(x)"=cos(x+pi/2)}}}
When you add 90<sup>o</sup> to an angle you get the sine in the NEXT quadrant,
which always has the opposite sign.
So {{{"f(x)"=-sin(x)}}}
    {{{"f(-x)"=-sin(-x)=-(-sin(x)^"")=sin(x)=-f(x)}}} <--odd function

D) all the above are odd functions  <--false, A is not
Edwin</pre>