Saturday, March 23, 2013

Rolled rubber roofing material, where can I buy it?

Q. I'm looking for a retail dealer in east Texas that sells rolled rubber roofing material at least 8 ft. wide.

A. don't think HD has it. and it is not really a DIY product. i've used it a few times and there are a few special methods you need to know.

try this site, they have someone in texas. i think you want to ask for edpm roofing: http://www.roofingproductsunlimited.com/aboutus.html

try: http://www.gaf.com/General/GAFIntro_MAIN.asp

also try: Modern Building Supply. 31209 State Highway 64. Wills Point, TX 75169 (903) 865-6762 [they're a little east of Dallas]

We need to replace roofing material-shingles or the metal ones that seem to be getting popular-?
Q. We have a simple 2 story farmhouse in the midwest US. Anyone have pros and cons on roofing materials, as to cost, durability, etc.? Thanks a bunch!

A. a good shingle roof is fine. but with the price of petroleum based products going so high, a metal roof may be more economical in the long run.

A wise old troll wants to make a small hut. Roofing material costs five dollars per square foot and wall mater?
Q. A wise old troll wants to make a small hut. Roofing material costs five dollars per square foot and wall materials cost three dollars per square foot. According to ancient troll customs the floor must be square, but the height is not restricted.
(a) Express the cost of the hut in terms of its height h and the length x of the side of the square floor.
(b) If the troll has only 2535 dollars to spend, what is the biggest volume hut he can build?

I already have a. I got 5x^2+12xh for a but I can't figure out b!

A. For b, what you have to do is maximize

h * x^2

while

5x^2+12xh = 2535

we can solve for h in terms of x, then use calculus to find the local extrema of [h * x^2]

h = (2535 - 5x^2) / (12x)

plug into

h * x^2

[(2535 - 5x^2) / (12x)] * x^2
=
(2535 / 12) * x - (5 / 12) * x^3

we'll call this f(x)

f(x) = (2535 / 12) * x - (5 / 12) * x^3


now we need to solve f'(x) = 0 so that we can find the local extrema.

f'(x) = (2535 / 12) - (5 / 4) * x^2

f'(x) = 0

(2535 / 12) = (5 / 4) * x^2

x^2 = 169

x = + or - 13

-13 is impossible, so x = 13

now we just plug this into f(x) (f(x) is the function for the volume only in terms of x)

(2535 / 12) * 13 - (5 / 12) * 13^3
=
10985 / 6
=
1830.83 cubic feet




Powered by Yahoo! Answers

No comments:

Post a Comment