# Thread: Plotting a graph - Trigonometric Function

1. ## Plotting a graph - Trigonometric Function

Hi Again guys,

I've been told that the following problem can be solved on excel fairly easily... but i'm unsure what i should do with it.

Could anybody guide me through the solution so i can practice some examples?

Here is a screenshot of the problem:

Thanks

2. You have,
$4\cos \left( x +\frac{\pi}{4} \right)$
That means, you will draw your regular cosine curve having an amplitute of 4 and the shift it to the left.

First draw the regular cosine of amplitude of 4. (dotted line)
Then use it to help you draw the real curve move to the left of $\pi/4$ (red line).

3. Thanks, that looks a little complicated though Perfect Hacker.. the examples we did at college on excel looked a little more simple.

I briefly remember we had a table of values on the excel spreadsheet, and then we had a graph which looked similar to the answer which was removed from this thread.

4. Originally Posted by c00ky
Thanks, that looks a little complicated though Perfect Hacker.. the examples we did at college on excel looked a little more simple.

I briefly remember we had a table of values on the excel spreadsheet, and then we had a graph which looked similar to the answer which was removed from this thread.
I removed my answer becuase I wasn't certain if my excel is set to radians or degrees.

I've reposted it below, you can decide.

5. Originally Posted by Quick
I removed my answer becuase I wasn't certain if my excel is set to radians or degrees.

I've reposted it below, you can decide.
For the record, all trig functions in Excel assume the argument is in radians. The inverse functions all give answers in terms of radians.

-Dan

6. Originally Posted by Quick
I removed my answer becuase I wasn't certain if my excel is set to radians or degrees.

I've reposted it below, you can decide.

RonL

7. Originally Posted by c00ky
Hi Again guys,

I've been told that the following problem can be solved on excel fairly easily... but i'm unsure what i should do with it.

Could anybody guide me through the solution so i can practice some examples?

Here is a screenshot of the problem:

Thanks
Something like:

8. So when V = 2.... x = ????

If you plot the graph over 360 degrees there are two answers..

I'm lost!

9. Both answers are correct and if you left the oscillator on you would continue to get two additional answers every 360 degrees

Oh and for those having trouble with Excel try Autograph, designed by mathematicians for teaching mathematicians. I think its pretty good and at college we're stuck with the older version without 3D graphing Get a 30 day trial from here:

http://www.autograph-math.com/

10. Originally Posted by Glaysher
Both answers are correct and if you left the oscillator on you would continue to get two additional answers every 360 degrees

Oh and for those having trouble with Excel try Autograph, designed by mathematicians for teaching mathematicians. I think its pretty good and at college we're stuck with the older version without 3D graphing Get a 30 day trial from here:

http://www.autograph-math.com/
The advantage of Excel is that it is a very common piece of software
and you are likely to meet it on most PCs you encounter. I would normally
never recommend a piece of commercial software for mathematical work,
but the solver in Excel is a killer application and I use it all the time.

(Commercial software is a strange concept, at home I run MS Office 95
under XP, which I bought a number of years ago for £5 of off e-bay)

Other than common tools like Office (though even here OpenOffice would
almost be a viable alternative if it weren’t for the Excel solver) I would never
recommend commercial software for teaching or research for Maths. The free
products are good and cheap.

RonL

11. Fair enough. I don't know many free ones though. The only one I've got is a wonderfully simple program that allows you to create graph paper to stick in other programs such as Word. I don't like Excel for little things really, like not drawing histograms properly.

12. Originally Posted by Glaysher
Fair enough. I don't know many free ones though. The only one I've got is a wonderfully simple program that allows you to create graph paper to stick in other programs such as Word. I don't like Excel for little things really, like not drawing histograms properly.
I've forgotten what its called but look for what ThePerfectHacker uses
it looks pretty good and is free. There is a link to its web page somewhere
in his posts (better still just wait till he reads this, I bet he posts the link