Question 5077
given {{{f(x)=-x^3+2x^2+2x+5}}} find f(-1), f(0), and f(1).


Functions are very straight forward, but a lot of student freak out. They are basically just a more professional approach of writing equations...basically.


f(x) = 2x + 1 means there is an equation (function) and you do what it tells you to do (the right hand side) to the value x (the thing in the bracket)


So, in this example, it says..take x, mutliply it by 2 and then add 1.


So, for your example: {{{f(x)=-x^3+2x^2+2x+5}}}

f(-1) says, put in the value of -1 everywhere instead of x..so do it:


{{{f(-1) = -(-1)^3 + 2(-1)^2 + 2(-1) + 5}}}
{{{f(-1) = -(-1) + 2(+1) - 2 + 5}}}
{{{f(-1) = +1 + 2 - 2 + 5}}}
f(-1) = +6


f(0) says, put in the value of 0 everywhere instead of x..so do it:


{{{f(0) = -(0)^3 + 2(0)^2 + 2(0) + 5}}}
{{{f(0) = 0 + 0 + 0 + 5}}}
f(0) = +5


you try the f(1) yourself.


jon.