how the he!! do you solve this??

[kappage]

ok i need to solve
F(x)= (3Cosx)/(2+Sinx) between -Pi < x < Pi (pi being 3.14.....)

I need to find the Zeroes, so when it cuts the X axis (it does it twice), Therefore it should look like this


0 = (3Cosx)/(2+Sinx)



Note: '/' means Divide.

Thanks

[kappage]

Well i have figured out the answers in Exact value form, which is -Pi/2 and Pi/2 but i onky found these values by graphing it and doing Guess and check.

[Alathald]

There may be another way to do this but I'm guessing that since you just finished integration by parts, you've moved on to things like numerical approximation methods and that means Newtons Method!

I'll just steal this lovely image from wikipedia:


So basically you just start at a random value that you believe is close to a root, x_0, and using the above formula solve for x_1. Then just rinse and repeat (use x_1 to find x_2, etc) until you've arrived at your desired level of accuracy (this is where programmable calculators come in handy).

[kappage]

Why the hell could i not think of that?!?! i did differntiation like that last year .... Thanks for pointing that out, and actually we have already done integration by parts.

Argh how did i not see that?!?!

[Alathald]

Just takes a bit of practice and like anything else you get a 'feel' for it over time. BTW I just noticed your sig, nice, just always remember to i^4 (ok that was bad but eh, math joke )