inverse function question
posted by elle .
Hey, I'm having trouble fully understanding absolute value graphs and I've been asked find the largest value of a so that f^1 exists for the function:
f: (efinity,a) > R where f(x)= logel2x1l
*note: i have used 'l' to represent the straight line indicating the it is an absolute value...
I know the answer is a=1/2 but i have no clue how to get that answer... Any help would be much appreciated :)

There is no such thing as the log of a negative number or zero. Because of the absolute value in the definition of f(x), the only value of x for which f(x) is not defined is x = 1/2.
An inverse function of f(x) can be defined for all x, but there will be two values of f^1(x) for each x , since two different x values, symmetric about a=1/2, give the same f(x)
I don't know what you mean by
f: (efinity,a) > R