I want to sketch y=4e^-2x
How would I do it? I know how the basic y=e^x looks, but I dont understand what you do when you have a negative power.
Sketching graph logariths/exponential C3 Watch
- Thread Starter
- 16-08-2013 18:49
- 16-08-2013 19:24
Can you see what I've just done? Now all you have left to do is apply transformations to go through
- Study Helper
- 16-08-2013 20:33
When x = 0, y = 4 so you can mark the point (0, 4) on the y-axis.
As x gets bigger and bigger, e^(-2x) gets smaller and smaller. However, e^(something) is never zero, whatever 'something' is, so the graph will never touch the x-axis. So from the point (0,4) you can draw a gently sloping curve downwards that approaches the positive x-axis as an asymptote.
For x < 0 , e^(-2x) is positive and increasing as x gets more and more negative, so your curve extends upwards to infinity as x becomes more negative.
To complete the analysis properly, differentiate y to reassure yourself that there are no turning points on the graph.