Comments on: Texas bound

By: blueollie

blueollie — Fri, 23 Nov 2007 12:55:31 +0000

Tammy, it was 16.65 feet, or in exact terms:

8/(sin(arctan(2^(1/3)))) + 4/(cos(arctan(2^(1/3))) which has a rational function expansion:

(8/(2^(1/3)))*((2^(2/3)+1)^.5) + 4*((2^(2/3)+1)^.5)

and can be obtained in the manner that your husband obtained it.

By: Tammy

Tammy — Fri, 23 Nov 2007 01:23:29 +0000

I had no success at the problem because my calculus is WAY too rusty (i.e. I have forgotten all of it). However, my husband, who is a total math genius (why he didn’t become a math prof, I’m not sure), still remembers everything from his calculus classes 20 years ago, even though he has not used it since. He did get an answer to the problem and wants to know if it was right. Of course I can’t find the answer now (we are sitting here remembering that it was ~18.6 feet?). He did the problem by coming up w/an expression for the length of the ladder based on the angle the ladder makes with the ground, set the first derivative to zero to find the minimum, and solved for the angle, which then gave him the length of the ladder. And yes, he did use similar triangles and lots of trig functions that I had almost forgotten all about !

By: blueollie

blueollie — Thu, 22 Nov 2007 03:15:50 +0000

Tammy, Jennifer, thanks for attempting the problem. There are two approaches and there are three similar triangles available to use.

I can understand why some are very “method” dependent; after all:

64/16 = 4 and you can get this answer by “canceling” the digit 6 in both the numerator and the denominator. So, a “right answer” doesn’t always mean “correct” and I doubt that many 8′th graders have the sophistication to grasp that there are really correct alternative ways to approach a problem. There are tons of incorrect alternative ways though!

By: vonster

vonster — Tue, 20 Nov 2007 19:08:55 +0000

Woo? Who’s the “woo”? The person who might believe in God or one of the barking moonbats who participated in the treasonous act of interfering with the movement of military equipment in a time of war and later stood up before the Olympia city council and stated “My name is Andrew Charles Hendricks, I was commissioned in 1986 as an intelligence officer in an underground revolutionary organization ..”

Who’s denying reality?

By: Jennifer

Jennifer — Tue, 20 Nov 2007 18:48:18 +0000

I was a math major in college, so I’ll have to ponder your assigned problem. I use math in my workplace, but business math, rather than calculus, trig or algebra, so I’m feeling rusty.
Luckily, I am still able to to do 8th grade math… I check my son’s homework frequently. My kids are so funny, though, if I do a problem in a different way than their teacher they insist I am wrong. (even if I have the right answer).

By: Tammy

Tammy — Tue, 20 Nov 2007 05:08:13 +0000

You’ve really got me going w/the calculus problem. Unfortunately, since it has been (gulp!) almost 20 years since I had calculus, and since I never use it for work, I really am missing something. You are going to post the answer sometime, right?

I do remember algebra and some rudimentary geometry, but that’s not going to do it. (I use algebra for work sometimes). Amazing how little math I need for my job, all things considered.

By: Seduction and Relationships » Blog Archive » Texas bound

Seduction and Relationships » Blog Archive » Texas bound — Tue, 20 Nov 2007 04:18:09 +0000

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