Science & Mathematics - 25 October 2007

The Question is:
What is the value of lim((x + "delta" x)^3 - x^3)/ "delta" x
if x=3
The answer is 3x^2 and thus 27.
How do you arrive at this answer? Can someone explain to me how to solve these kinds of questions?

2007-10-25 15:49:47 · 2 answers · asked by Anonymous in Mathematics

I am - let me multiply!!!!!!!!!!

2007-10-25 15:48:21 · 4 answers · asked by Brielle 3 in Biology

find the volume of the solid obtained by the rotating the region bounded by the given curves about the specified axis:
y=1/x^3
y=0
x=3
x=7
about y=-4

2007-10-25 15:47:36 · 2 answers · asked by Anonymous in Mathematics

2007-10-25 15:47:19 · 5 answers · asked by Anonymous in Biology

people need to know this stuff. http://www.youtube.com/watch?v=zORv8wwiadQ

2007-10-25 15:45:15 · 6 answers · asked by Pink Panther 4 in Physics

The partly melted, plastic-like rock of the lower mantle is called the _____________.

thanks, this is about Earth's Interior.

2007-10-25 15:40:59 · 4 answers · asked by 5ipodsathome 1 in Earth Sciences & Geology

1. A vertical circular cylinder has radius r ft. and height h ft. If the height and radius both increase at the constant rate of 2 ft/sec, then the rate in square feet per second at which the LATERAL SURFACE AREA increase is???

2. If f(x) = 10^x and
10^1.04 aprrox. equals 10.96
wat is the approx. value of f'(1)?

2007-10-25 15:38:39 · 2 answers · asked by Anonymous in Mathematics

2007-10-25 15:37:53 · 3 answers · asked by Alan 1 in Astronomy & Space

2007-10-25 15:36:23 · 2 answers · asked by PigDestroyer23 1 in Biology

is nature ever really in balance or are ecological systems involved in a process of constant change

2007-10-25 15:35:42 · 4 answers · asked by fengzengjason 1 in Biology

2007-10-25 15:33:48 · 17 answers · asked by bungalo 1 in Geography

Survival of a group of breast cancer patients is 100 at year 0, 100*X at year 1, 100*X*X at year 2, 100*X*X*X at year three and so on to year 10. How do I find the nth year survival?

2007-10-25 15:30:14 · 2 answers · asked by Richy 2 in Medicine

2007-10-25 15:29:48 · 2 answers · asked by Softball maniak 1 in Botany

Say I had four 12-volt lead-acid batteries connected in series as a battery pack.

Could I buy a 48-volt rated charging unit that would charge them all at the same time?

I have heard of issues with other battery chemistries where one battery happens to become under-charged in a series string (due to slight internal resistance differences, etc).

Would it be better to disassemble the pack and charge the batteries individually with an appropriate 12-volt charger?

Please advise. Thanks!

2007-10-25 15:29:02 · 3 answers · asked by Ubi 5 in Engineering

I need instutions on how to isolate the acid without getting hurt.

2007-10-25 15:27:42 · 3 answers · asked by Anonymous in Chemistry

2007-10-25 15:27:36 · 4 answers · asked by Anonymous in Botany

What will be the final temperature of the water in an insulated container as the result of passing 4.76 g of steam [H2O(g)] at 100.0°C into 110.5 g of water at 25.0°C? (Hvap° = 40.6 kJ/mol H2O)

2007-10-25 15:25:31 · 2 answers · asked by Anonymous in Chemistry

Out of 80 problems these are the only couple I can't get so I figure I'm doing good Any help on these would be greatly apreciated since there all due tommrow.

Thanks


Find dy/dx by implicit differentiation


1.) cot(y)= x-y


2.) x=sec(1/4)

2007-10-25 15:25:24 · 2 answers · asked by Anonymous in Mathematics

Thankyou!

2007-10-25 15:25:14 · 4 answers · asked by Ronald H 1 in Earth Sciences & Geology

A balloon filled with 31.9 mol helium has a volume of 715. L at 0.0°C and 1.00 atm pressure. The temperature of the balloon is increased to 68.0°C as it expands to a volume of 893. L, the pressure remaining constant. Calculate q, w, and E for the helium in the balloon. (The molar heat capacity for helium gas is 20.8 J/°C·mol.)

2007-10-25 15:23:33 · 1 answers · asked by toocool 1 in Chemistry

A 1.397 g sample of thymol, C10H14O(s) (a preservative and a mold and mildew preventative), is burned in a bomb calorimeter assembly. The temperature increase is 11.23°C, and the heat capacity of the bomb calorimeter is 4.68 kJ/°C. What is the heat of combustion of thymol, expressed in kilojoules per mole of C10H14O?

2007-10-25 15:22:07 · 1 answers · asked by toocool 1 in Chemistry

Salicylic acid, C7H6O3, has been suggested as a calorimetric standard. Its heat of combustion is -3.023 103 kJ/mol C7H6O3. From the following data determine the heat capacity of a bomb calorimeter assembly (that is, the bomb, water, stirrer, thermometer, wires, and so forth).


mass of salicylic acid burned: 1.111 g
initial calorimeter temperature: 23.07°C
final calorimeter temperature: 29.55°C

2007-10-25 15:21:41 · 2 answers · asked by toocool 1 in Chemistry

In a coffee-cup calorimeter, 1.20 g of NH4NO3 is mixed with 76.0 g of water at an initial temperature of 25.00°C. After dissolution of the salt, the final temperature of the calorimeter contents is 23.21°C. Assuming the solution has a heat capacity of 4.18 J/°C·g and assuming no heat loss to the calorimeter, calculate the enthalpy change for the dissolution of NH4NO3 in units of kJ/mol.

2007-10-25 15:21:17 · 1 answers · asked by toocool 1 in Chemistry

yeh

2007-10-25 15:21:09 · 5 answers · asked by Anonymous in Biology

please

2007-10-25 15:17:49 · 1 answers · asked by Anonymous in Biology

Simple one or the other. Let the debate begin!

2007-10-25 15:15:42 · 22 answers · asked by Anonymous in Biology

I've heard of it a couple of times, but never researched it.

2007-10-25 15:12:22 · 10 answers · asked by Deenie 6 in Paranormal Phenomena

pls answer my question good helper people b/c tomorrow (oct. 26, 2007) is my quiz day and idk what is the answer so pls help me understand this pls. thnx and plus i need to ask another bout the question again, How does the role of chlorophyll compare with the roles of CO2 and H2O? thnx

2007-10-25 15:11:14 · 6 answers · asked by Anonymous in Biology

2007-10-25 15:11:06 · 4 answers · asked by reka _baby 1 in Mathematics

I need to do a statistical study with relation to meteorology. I need some sort of topic to research using statistical data. Other ideas used in the past were:

-El Nino / La Nina Impact on Flying Conditions

-Compare the design of the LLWAS system to the scales of downbursts and tornados to determine if it would be possible to detect a tornado with such a system.

2007-10-25 15:10:22 · 2 answers · asked by Anonymous in Weather