Math Is Fun Forum

parallax

Member

Registered: 2008-04-09

Posts: 1

asd

I think this is right, but if you have a moment to check it, that'd be great.

Problem:

Where A, B, C, D are positive and 0<C<1.  Find the sum of A+B+C+D if the first maximum to the right of the y-axis occrus at

and the first minimum (to the right of the y-axis) occurs at

.

My Solution:

A+B+C+D=22/3

Only part that I'm kind of unsure about is C. 

Daniel123

Member

Registered: 2007-05-23

Posts: 663

Re: asd

EDIT: Ignore me.

Last edited by Daniel123 (2008-04-09 07:09:49)

mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: asd

That all looks perfect to me.

It's easy enough to check though - the bit inside the sin function must equal π/2 for the maximum and 3π/2 for the minimum, so plugging in the given values of x and checking should be enough to confirm it. (As long as you're certain about B)

Welcome to the forums, by the way!

---

Why did the vector cross the road?
It wanted to be normal.

parallax

Member

Registered: 2008-04-09

Posts: 1

Re: asd

Thanks for the welcome.    Yeah, I love this site.  I'm wishing I had found it sooner.