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# C3 functions

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1. http://www.examsolutions.net/a-level...e/paper.php#Q5

part c i don't understand why the range is just -k

usually i let x=0 and e to the 0 makes 1 so from my logic(which isn't right this time) i got 1-k
2. e^(2x) is always greater than zero (draw the graph)

So e^(2x)-k is always greater than -k.
3. (Original post by thegreatwhale)
http://www.examsolutions.net/a-level...e/paper.php#Q5

part c i don't understand why the range is just -k

usually i let x=0 and e to the 0 makes 1 so from my logic(which isn't right this time) i got 1-k
For the graph f(x) = e^x, you know there is an asymptote at f(x) = 0.

If the graph is e^2x, the asymptote will not move.

The -k means all y values go downwards by k, and hence, since y must be greater than 0, it now must be greater than -k.
4. (Original post by Math12345)
e^(2x) is always greater than zero (draw the graph)

So e^(2x)-k is always greater than -k.
(Original post by JLegion)
For the graph f(x) = e^x, you know there is an asymptote at f(x) = 0.

If the graph is e^2x, the asymptote will not move.

The -k means all y values go downwards by k, and hence, since y must be greater than 0, it now must be greater than -k.
ah thanks all

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