yeh but remember methods is a scewed population, you get people above the average sort of vce intelligence doing it, because those that arnt do further or no maths. so thats 74% of an already smart population.. so dont worry about it

anyway um do you get what i mean by 1:1? because for a parabola, a y value is going to correspond to two x values.. ie if you draw a horizontal line accross the graph, its going to hit the graph in 2 points.

for a graph to have an inverse, it CANT do that. it can only hit it in one point. therefore, for an inverse you need to work out what part of the graph gives you only a value of x for each y value. for a parabola, you simply cut it down the middle. both halves can have an inverse.

like for that one above you could have an inverse from neg infinity to 3, and then from 3 to positive infinity. yeh? except in the question they've already defined the upper boundary as positiv infinity.. therefore you know its the '3 to pos infinity' half of the of the graph.

do you get it kinda? im not sure how else to explain it. find the section on inverses in your text book