Quote:
Originally Posted by belly_ttt 4) here is part of a math question I couldn't find out why: Which is the graph of y= -(x-2)2 (2 outside the bracket means square)? Graphs drawn below. And here was the solution: If f(x) = -x2 , the given equation, y= -(x-2)2, represents f(x-2) How come they got the last line? |
I'll explain the Maths one. (You can use a ^ to signify 'to the power of')
Let
x = 5 (for illustration. x will remain 5 for the whole exercise)
f(x) = - x^2
f(x) is a function which takes any value (x), squares it, then negates it.
So, if x = 5, f(5) = - x^2 = -25
In this case, x-2 is 5-2 = 3, so f(3) = -9
So f(x-2) = -9
And y = -(x-2)^2 = - (5-2)^2 = -(3)^2 = -9
So f(x-2) = y = -(x-2)^2
But put simpler, you can substitute anything for x
If you change f(
x) to f(
x-2), then -
x ^2 becomes -
(x-2)^2, which is y.
And it even works without colours! 