The function f is defined by f(x) = 2x^2-12x+13 for xk, where k is a constant. It is given that f is one-one function. State the smallest possible value of k

Question

The function f is defined by f(x) = 2x^2-12x+13 for x>k, where k is a constant. It is given that f is one-one function. State the smallest possible value of k

anonymous · Answer

Find the smallest k so for x>k f is strictly increasing and thus one to one

anonymous · Answer

This a parabola that opens up. Find the x coordinate of the vertex and you will be done

anonymous · Answer

Plz help me ...how to find the vertex

anonymous · Answer

Or can i use a(x+b)^2+c to solve this question by finding the value of b

anonymous · Answer

Look at the plot http://www.wolframalpha.com/input/?i=plot++2x^2-12x%2B13++from+x+%3D2+to+x%3D4

anonymous · Answer

You can deduce that the vertex is at x=3

anonymous · Answer

You also can use the derivative and see when it is zero