Consider the function f(x) = x - x^2 on the interval (0,1). Which of the following statements is true?
a. f is increasing
b. f is decreasing
c. f is constant
d. f is neither increasing, nor decreasing, nor constant

Question

Consider the function f(x) = x - x^2 on the interval (0,1). Which of the following statements is true?
a. f is increasing
b. f is decreasing
c. f is constant
d. f is neither increasing, nor decreasing, nor constant

anonymous · Answer

do you know what the vertex is ?

anonymous · Answer

Do you know anything about x^2 if 0<x<1? How does it compare to x?

anonymous · Answer

No that's all the question offers -_-

anonymous · Answer

actually what i meant was not "did they tell you the vertex" but rather "do you know how to find the vertex?"

anonymous · Answer

ax^2+bx+c=0 or y=ax^2+bx+ ?

anonymous · Answer

the vertex of $y=ax^2+bx+c$ is $-\frac{b}{2a}$ 
you have $y=-x^2+x$ so you your example $a=-1,b=1$

anonymous · Answer

i should be more precise and say "the first coordinate of the vertex is $-\frac{b}{2a}$"

anonymous · Answer

Ok, so where do go from there to get the answer?