- Wed Oct 26, 2011 11:07 pm
- Forum: Calculus
- Topic: Which is where? Understanding function and derivatives
- Replies:
**1** - Views:
**1705**

I have an exercise that I sorta get, but I need some help to be sure I'm getting it right. The problem is about determining the effect of the length of a contract on a monthly payment for a car purchase. The price and interest rate are fixed. P = f(t) is the monthly payment in $, and the contract le...

- Sat Jul 23, 2011 11:34 pm
- Forum: Trigonometry
- Topic: Fresnel Lens project
- Replies:
**10** - Views:
**5014**

I've been thinking about this problem for HOURS, even days. Its not at all like I'm trying to avoid that. This material is simply not familiar to me. You clearly have both experience and expertise. Maybe you can't recall a time when you didn't know this, and it now seems simple. But from my perspect...

- Sat Jul 23, 2011 9:43 pm
- Forum: Trigonometry
- Topic: Fresnel Lens project
- Replies:
**10** - Views:
**5014**

Thanks I got that one now. Next, I need to show that phi'1 + phi'2 = beta. If the same strategy applies, I can see a right angle formed from the origin of phi'2 and the terminal side of beta. I can see another from the origin of phi'1 to the vertical line that is 90deg. But I can't see how these sha...

- Sat Jul 23, 2011 5:32 pm
- Forum: Trigonometry
- Topic: Fresnel Lens project
- Replies:
**10** - Views:
**5014**

Here's another try- thanks for the suggestion. So, from the first right angle, I can make the addition equation phi2 + alpha = 90. The second equation would be beta + alpha + theta2 = 90. Is this what you mean by addition equations? Sorry to be so dense, but I'm not getting how these show how phi2 =...

- Sat Jul 23, 2011 3:12 pm
- Forum: Trigonometry
- Topic: Fresnel Lens project
- Replies:
**10** - Views:
**5014**

Do you do whiteboard on line tutoring?

- Sat Jul 23, 2011 1:34 am
- Forum: Trigonometry
- Topic: Fresnel Lens project
- Replies:
**10** - Views:
**5014**

Arggh. If the right angle you identified is created by the initial side of angle Beta, and the intial side of angle theta 2, are the equations you suggest to find angle alpha? Maybe (theta-90) - (beta-90)? to get angle alpha? Then the ref angle of phi2 = alpha = ref angle of (beta + theta2)? Is that...

- Wed Jul 20, 2011 3:44 pm
- Forum: Trigonometry
- Topic: Fresnel Lens project
- Replies:
**10** - Views:
**5014**

Thanks so much. I'll give that a try.

I have a test tomorrow, so I'll have to set this aside till after the test. But that's what I was looking for.

Stress level decreasing..

Wayne

I have a test tomorrow, so I'll have to set this aside till after the test. But that's what I was looking for.

Stress level decreasing..

Wayne

- Wed Jul 20, 2011 2:14 am
- Forum: Trigonometry
- Topic: Fresnel Lens project
- Replies:
**10** - Views:
**5014**

I have a big project- worth half a test- and I need some help. I don't want anyone to do the work for me- just help me get unstuck, and point to what I should be looking for. The project gives a few illustrtions, and then asks some questions. The actual assignment can be found at http://books.google...