Science & Mathematics - 11 January 2007

I have 3 questions.

The volume of a rectangular box is 16m^3. The box has a square base and top. The material for the base costs $7.25/m^2, for the top costs $2.25/m^2, and for the sides coss $4.25/m^2. For practical reasons, no dimension may be less than 1m. Determine the dimensions that will minimize the cost of the materials for the box. Show all your calculations and include a labelled diagram.
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A man is at point A on a bank of a straight river, 3km wide, and wants to reach point B, 8km downstream, on the opposite bank. He could row his boat directly across the river to point C and then run to B, or he could row directly to B, or he could row to some point D between C and B and then run to B. If he can row at 6km/h and run at 8km/h, how far from B should he land t reach B as soon as possible? Show all your calculations.
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A Norman window is made up of a semicircle and a rectangle. The total perimeter of the window is 32m. Determine max area of window. Show calculations.

2007-01-11 01:30:33 · 2 answers · asked by Anonymous in Mathematics

2-3 sentences

2007-01-11 01:30:20 · 3 answers · asked by Ba'kon 1 in Biology

why not brown or bush coloured?

2007-01-11 01:29:48 · 10 answers · asked by geo 1 in Zoology

2007-01-11 01:29:28 · 4 answers · asked by Erico S 1 in Astronomy & Space

2-3 sentences

2007-01-11 01:29:24 · 2 answers · asked by Ba'kon 1 in Biology

Name 2 cross-breeds of each-
Cow
Buffalo
Hen

2007-01-11 01:27:53 · 4 answers · asked by divyafairies 1 in Zoology

a computer operator can input 90 pieces of data per minute. how long will it take to the nearest minuite to input 55170 pieces of data??????

2007-01-11 01:27:46 · 6 answers · asked by steve 2 in Mathematics

2007-01-11 01:25:01 · 18 answers · asked by jais 1 in Geography

ok well the question is this, i forgot how to do percentages heres my problem how do i convert this data to percentage:
lets say i ran in 16 races and won 7 times.
how can i turn these numbers into percentage, i want to know what is my percentage of winning 7 races out of 16, please can you help and also please show the way you done it thanks.

2007-01-11 01:22:59 · 10 answers · asked by stef 2 in Mathematics

x^2 - 5x + 3 for x = 6........12 - 30 + 3 = -15
6 - 4x for x = -5.........6 - 4x = 26

2007-01-11 01:22:28 · 4 answers · asked by sparky691970 1 in Mathematics

2007-01-11 01:14:24 · 8 answers · asked by Anonymous in Geography

2007-01-11 01:11:58 · 22 answers · asked by Anonymous in Astronomy & Space

I forgot about the warning, and accidentally took the prozac with my vitamins and got TERRIBLE heartburn. Is that why they say not to take together? Do they react or something?

2007-01-11 01:11:48 · 3 answers · asked by misscongeniality711 2 in Medicine

how can you prove that (a*b)^2 = a^2*b^2

2007-01-11 01:09:14 · 7 answers · asked by nikos k 1 in Mathematics

2007-01-11 01:04:07 · 0 answers · asked by green wheat 2 in Medicine

its about 96 all.

2007-01-11 01:03:42 · 2 answers · asked by jenny mae m 1 in Chemistry

Why is it that in uk we use plural and in US they use singular. Same with Overheads and Overhead?

2007-01-11 01:03:06 · 18 answers · asked by Anonymous in Mathematics

The specific question was

How would one overexpress an important protein. Include the method used to enable rapid one-step purification.


My answer is

Isolote the gene encoding for the protein and ligate to His-tag. . Then clone modified gene into a LAC promoter in a bacterial artificial chromosome and tranform into E-coli, make sure the BAC has Ampicillin resistance gene. Then select for bacteria having Ampicillin resistance. intruduce lactose to induce LAC promoter. Then remove proteins and apply to affinity medium to which the HIS tag will bind and then wash to remove unwanted proteins. then elute wanted proteins using imidazole.

what do you think of my answer?

2007-01-11 01:02:00 · 3 answers · asked by nikos k 1 in Biology

the countries are fighting to go and expolre the space.why?

2007-01-11 01:00:36 · 8 answers · asked by velavan v 1 in Astronomy & Space

Pls..nid ur answers..its for me physics class. thank you

2007-01-11 00:57:26 · 3 answers · asked by Anonymous in Physics

A machine is powered by 3 similar batteries. It will only work if at least 2 of the batteries are working. P(any one battery breaks in less than 200hours)=.7. P(any one battery breaks in less than 100 hours)=.2. Find the probability the machine will work between 100 and 200 hours.

2007-01-11 00:57:19 · 6 answers · asked by kate 1 in Mathematics

2007-01-11 00:54:16 · 6 answers · asked by Anonymous in Weather

2007-01-11 00:52:55 · 2 answers · asked by Priyank J 1 in Engineering

Who was affected by the storm that hit Saskatchewan Yesterday ?
and were you at home?

2007-01-11 00:51:56 · 1 answers · asked by ? 2 in Weather

2007-01-11 00:51:35 · 10 answers · asked by Silkie1 4 in Zoology

2007-01-11 00:47:31 · 7 answers · asked by oriprlo 1 in Zoology

How should we describe this number?

2007-01-11 00:45:56 · 2 answers · asked by Anonymous in Mathematics

2007-01-11 00:45:48 · 4 answers · asked by sweet_andsimple23 1 in Biology

It is very windy here at the moment - in fact I've just been blown over!

What does the wind actually do? Has it any uses?

2007-01-11 00:45:47 · 2 answers · asked by Anonymous in Weather

EXAMPLE 1. Determine the number and situation of the real roots of
the equation x^5 - 3 x - 1 = 0.

The Sturm chain is

y = x^5 - 3 x - 1,

y' = 5 x^4 - 3,

y'' = 12 x + 5,

y''' = 1.

where y'= dy/dx

The signs of f for x = -2, -1, 0, +1, +2 are

-----------------------
x | f0 | f1 | f2 | f3
-----------------------
-2 | - | + | - | +
-1 | + | + | - | +
0 | - | - | + | +
+1 | - | + | + | +
+2 | + | + | + | +
-----------------------

The equation thus has three real roots: one between -2 and -1, one
between -1 and 0, one between +1 and +2. The other two roots are complex.

Question:
How do you know that the equation has three real roots between -2 and -1, one
between -1 and 0, one between +1 and +2???
Please explain!!

2007-01-11 00:43:11 · 1 answers · asked by Anonymous in Mathematics