Mrs. RickJay and I are trying to get Excel to graph a sinusoidal function. We simply cannot get it to calculate the right values.
Here’s what we’re doing; in one column we have time intervals from 1 to 50, 1,2,3,4 and so on. In Column B we are attempting to find the sinusoid of a 1200 Hz frequency with no phase shift. Now, according to every damned formula I can find, this is the formula:
=SIN(2*PI()1200T)
Now, unless I’m crazy, what this formula should do is calculate 2 times PI times 1200 times the time (which starts at 1, 2, 3, etc.) and then take the sine of that number, right?
Well, now, I always thought the sine of any positive number was a value between -1 and 1, right? And that’s what this should do. 2 times PI times 1200 times, say, 1 (for the first time interval) is 7539.822359 or something like that. And the sine of that is -.349. With me so far?
Okay, no problem. So we typed that into an Excel cell. And it gave us…
-407733E-13
Uh… WHAT??? What the hell’s that?
I’ve gone over the formula again and again and again. Mrs. RickJay has gone over it again, and again, and again. The formula’s typed in right. If I take out the SIN function it gives me 7539, which is right. If I do SIN(7539.822) it gives me -0.349, which is also right. But if I try SIN(function) it simply will not work. In fact, if we calculate (2*PI()1200time) in one cell and do =SIN(cell reference) in another, you get 7539.822 in the first cell, but it still does not work in the second cell. Why? What are we doing wrong?