Next, just drag your box all the way down, just like the previous step. Also, make sure you put in asterisks for multiplication signs, it makes sense to write 2B1, but it won't work, write in 2*B1. In this case, write "=2*B1 3+6*B1 2-12*B1+4" in the C1 box (use shift+6 to do the power sign in excel, instructables just superscripts everything when I use it here.) Notice that it's the same function as before, except instead of X we're using B1.
Wherever you have an undefined variable (x) just put in B1,B2, etc depending on which cell you're working on.
Now just plug in your function so that every cell is a function of the one next to it. Drag this box down until you reach the other end of your X range, in this case 5. It's hard to describe, look at the third picture. Place your cursor over the bottom-right corner of the cell, there should be a small black square, click it and drag it down, as you drag it, you should see the numbers slowly getting bigger. The dollar signs tell your spreadsheet program to reference A2 regardless of which cell you copy the equation into. Then in the cell below (B2) type in "=B1+$A$2" without the quotation marks, hit enter. Put your initial value at the top of the next column over, the second picture below shows you what this should look like. For my computer, below 1000 cells usually works well. Once your columns are more than a few thousand cells long, it takes forever for your computer to process them all at once. You could also use 0.01 (it would be a bit more accurate) but you generally don't want to go smaller. Also set your step size, I set mine at 0.1. First, you want to put your x values down in your spreadsheet, I made mine go from -5 to 5. We chose this equation because finding it's derivative and antiderivative will be easy, so we can check our answer. It's the same equation shown in the picture below, which looks a lot nicer.
To demonstrate, we're going to use the equation y=2x 3+6x 2-12x+4. If you don't know how to use any of these programs, don't worry, it's pretty easy learning. First thing you're going to need is a spreadsheet program like Excel, Numbers, or OpenOffice.
0 kommentar(er)
