Wednesday
September 3, 2014

Posts by Joe


Total # Posts: 2,049

alegbra
true i am sorry for that ! thanks Reiny for correcting :)
April 29, 2010

alegbra
(x-5)(x+19) = x^2 + 14x - 95 second degree equation (y = a*x^2 + b*x +c), must use Delta = b^2 - 4*a*c to solve it *** Solution *** Delta = (14)^2 - 4*(1)*(-95) = 596 > 0 two solutions: x1 = (-b-sqrt(Delta))/(2*a) x2 = (-b+sqrt(Delta))/(2*a) Numeric Application : x1 = -19 ...
April 29, 2010

Calculus
to calculate the max of any function (absolute or relative) u must derivate it and find the value of x that cancels that derivative. for your case, here is the solution : *** Solution *** let's derive f(x): f'(x) = 5 - 5*e^(5x) condition that we impose : f'(x) = 0 ...
April 28, 2010

8th grade math
Hello the 2 variables that u have to conider are the total sales that we will call x in our case, and Kenisha's income that we will call y A) if we translate the first sentence to an equation, we understand that she earns a fixed amount + a percentage on the total sales, ...
April 28, 2010

Math
Right
April 28, 2010

math
A plane that flies 170 miles per hour is flying 510 miles. How long will the trip take?
April 28, 2010

Physics
objects have various reflexion indexes, for a mirror it's close to 1, so this is why it reflects almost everything the law applies for everything, but the reflected ray may be very very weak
April 28, 2010

Science chemistry
.0118 moles benzoin .288 moles HNO3 How do I do the ratio?
April 27, 2010

Science chemistry
Assume 2.5 grams of benzion and 12.0 mL of 15.8 M nitric acid (density = 1.51 g/mL) was used in the experiment . What is the mole to mole ratio of benzion and nitrate ion.
April 27, 2010

Physics
An RC-circuit has a time constant of 6x10-3 seconds. The capacitor stores a maximum energy of 8 J, when charged using a 3-Volt battery. Using the same battery, we want to increase tenfold the amount of stored energy, while keeping the same time constant (to ensure that the ...
April 27, 2010

Physical Science
What are the various properties of a substance that determine its heat capacity?
April 27, 2010

Physical Science
What are the various sources of heat?
April 27, 2010

Math
The mean of a sample of 25 was calculated as xbar = 500. The sample was randomly drawn from a population whose standard deviation is 15. Estimate the population mean with 99% confidence. B.) Repeat part (a) changing the population standard deviation to 30. C.) Repeat part (a) ...
April 27, 2010

college-physics
In a particular region of space, the magnetic and electric fields have energy densities of 0.2 J/m3 and 4 J/m3 , respectively. Calculate the strength of the magnetic and electric fields in this region.
April 26, 2010

science
after spraying crops with ddt for several years, farmers found that populations of insect pests rebounded. one reason was that insects had developed resistance to the insecticide. suggest another reason, based on what you know about populations, pyramids, predators and ...
April 26, 2010

math
Jen and Heather went to lunch. jen had $8.00 for the bill. Gayle had 3/5 of the bill. how much did Gayle pay.
April 26, 2010

algebra 1
Given the data points (2, 9), (-4, 8), and (7, 3), the relationship shows a direct variation.
April 22, 2010

math
the ratio of girls to boys in the fifth form is 5;4 there are 144 pupils in the fifth form. how many are girls and how many are boys?
April 22, 2010

math
what is the unit rate of 2 for $4.98
April 20, 2010

8th grade
I guess you couldn't solve it. Here's how to solve it x^2(3x-8y) =25(-15-32) =-1175
April 20, 2010

chemistry
What volume of .200M NaOH will be required to react completely with 32 mL of .15M HNO3
April 20, 2010

Algebra
THe function h(t)=-16t^2+v0t+h0 describes the height in feet above the ground h(t) of an object thrown vertically from a height of h0 feet, with an initial velocity of v0 feet per second, if there is no air friction and t is the time in seconds sine the object was thrown. A ...
April 19, 2010

Algebra
THe function h(t)=-16t^2+v0t+h0 describes the height in feet above the ground h(t) of an object thrown vertically from a height of h0 feet, with an initial velocity of v0 feet per second, if there is no air friction and t is the time in seconds sine the object was thrown. A ...
April 19, 2010

Economics
In a one-shot game, if your rival advertises and you advertise, he will earn $7 million and you will earn $2 million in profits. If neither of you advertise, you will make $4 million and he will make $2 million. If you advertise and your rival does not, you will make $3 ...
April 19, 2010

math
Marissa plans to cut a wire that is 5 feet 3 inches long. How long should each of the cut pieces be if she wants 7 equal pieces of wire? Find the twenty-second term of an arithmetic sequence if the first term is 4 and the common difference is 10. Find the twenty-second term of...
April 19, 2010

math
what is the unit rate of 2 for $4.98
April 18, 2010

college algebra
x^2+34x+c
April 18, 2010

History
How did human history in North America during the period described in the Prologue differ from the events of Asia, Eurasia, and Europe?
April 17, 2010

math
How do you do this question? A shipment of 25 television sets contains three defective units. In how many ways can a vending company purchase four of these units and receive (a) all good units, (b) two good units, and (c) at least two good units.
April 17, 2010

math
When a soccer ball is kicked with a vertical speed of 25 m/s its height, h metres, after t seconds is given by the equation h=-5t^2+25t a) how long after it is kicked is the soccer ball at a height of 30 m ? b) How long is the soccer ball in the air?
April 15, 2010

Business
Consider the wide spectrum of business organizations, ranging from gigantic corporations to working at home. Describe at least three types of business organizations that you are familiar with or that you would like to know more about. How is each one advantageous to the ...
April 13, 2010

Investments
You are to analyze and compare one company from the holdings to another company that the Fund does not currently own within the same sector. (USB, PNC). Your analysis will include both fundamental and technical analysis. For the fundamental analysis, you are to calculate the ...
April 13, 2010

chemistry
How would one calculate the equilibrium pressure of Sodium bicarbonate and citric acid in water (think Alka Seltzer), reacting in a closed volume. The pressure builds up to a point, where the reaction slows due to pressure build up. How do I calculate the equilibrium pressure ...
April 12, 2010

Pre Calculus
Verify the following identity 2 tan x/1+tan^2 x = sin 2x
April 12, 2010

Anatomy and Physiology
What structure still works to pump out sodium and potassium in while resting to maintain the concentration gradient? a. cell body b. axons c. dendrites d. synapse All of the following are characteristic of the passive potassium channel except _____. a. found on cell body, ...
April 9, 2010

Anatatomy and Physiology
The ability of a specific tissue or organ to respond to the presence of a hormone is dependent on:
April 8, 2010

chemistry
Thanks!
April 6, 2010

chemistry
how do you how do you find the mass of a solution, given the density is 1.022 g/mL.
April 6, 2010

e
Invigorate means gives you renewed energy, so I guess D would be correct. Kind of a funny question the way it's written.
April 5, 2010

math
make a possibility tree: turkey roast beef ham cheese Multiply the number of sandich types (4) times the number of drink types (3) times the number of desserts (2) and you get 24 possible combos. It's that simple (go figure!)
April 5, 2010

Math
Probability: There are 10 yellow cards, 6 green, 9 orange, and 5 red cards in a stack of cards turned face down. Once a card is drawn, it is not replaced. What is the probability that you will select 2 yellow cards?
April 5, 2010

4th grade
Funny problem. Is it worded correctly? Each side of the dog house would be 7 feet. Is that what you're looking for?
April 5, 2010

spanish
Yo tengo las clases de matematicas, ingles y sciencia.
April 5, 2010

Hypothesis testing
Can we prevent flooding in our communities
April 2, 2010

8th grade algebra
what is the square root of 9x (to the power of 8) Explain too?
March 30, 2010

Math
computing grades. the fith test counts as double ( and i got the answer 74, so how much would it be as double?. thanks!
March 30, 2010

spelling
spell whirlwind correctly
March 25, 2010

math
Jen,amy,linda,max and jenny are compteting to fill two remaining spots on the chess team. How mant different combinations are possible for filling the two spots? 120,60,20,or 10
March 22, 2010

math
Tom recieved 90 votes in the student council election. That was 30% of the total votes cast. How many votes were in the election? 200 270 300 360
March 22, 2010

Calculus
given y=sec(x^2)ln(2x^5) find dy/dx
March 22, 2010

Calculus
find f'(x) f(x)=(3x^2-4)^5 / √2x-1
March 22, 2010

Calculus
find f'(x) f(x)=cos(2x)tan(2x)/2√x
March 22, 2010

Calculus
find f'(x) f(x)=x^5lnx
March 22, 2010

Calculus
find f'(x) f(x)= sin(3x)/2x^2-4
March 22, 2010

Chemistry
The example I was referring to was acetic acid.
March 21, 2010

Chemistry
There exists a correlation between maximum electrostatic potential and acid strength. As pKa decreases (acid strength increases), the maximum electrostatic potential for a molecule increases. Given a particular acid, is there any way to determine the maximum electrostatic ...
March 21, 2010

Art
What are the differences between film and popular cinema?
March 19, 2010

Chemistry
What range of values for electrostatic potential is characteristic of strong acids? What range is characteristic of weak acids? Why is there a correlation between electrostatic potential and acid strength?
March 16, 2010

english
please give me a good thesis statement on the topic "Aids in Africa"
March 15, 2010

math
How many times does each digit (0 through 9) appear in a list of counting numbers from 1 to 100 inclusive?
March 14, 2010

Finance
The dividend yield is 5.7%
March 14, 2010

intermediate algebra
where did you get the 750? I have a similar problem here: a farmer wants to build a rectangular pen using a side of a barn and 60ft of fence. find the dimensions and area of the largest such pen
March 8, 2010

math
A total of four students belong to all three teams, the baseball, basketball and football team. These four students represent 10% of the baseball team, 25% of the basketball team and 8 1/3 % of the football team. There are 20 students who are just on two teams. What percent of...
March 7, 2010

math
Find the smallest positive whole number with exactly ten positive factors and list the factors.
March 7, 2010

math
Friendly's Clothing Store bought handkerchiefs, six for $10, and sold them 4 for $10. They made $60 profit. How many handkerchiefs did they sell?
March 7, 2010

math
Find the four-digit number described by these three clues. 1) The first digit is one-third of the third digit. 2) The fourth digit is twice the second digit. 3) The first and third digits add up to twice the sum of the second and fourth digits.
March 7, 2010

Physics
There are two particles of charge +Q located on the top left and bottom right corners of a square. What is the direction of the net electric field at the point on the bottom left corner of the square? And also what would be the general equation be for finding the potential ...
March 7, 2010

physics
There are two conducting spheres of different sizes, both with the same negative charge. If they are connected with a conducting wire, the charge would therefore flow from the smaller to the larger. Am I correct? Thanks!
March 7, 2010

physics
If there are two conducting spheres of different sizes, but of a same negative charge and they are connected with a conducting wire, does the charge flow from one sphere to the other?
March 7, 2010

English
Thank you.
March 6, 2010

English
What is the difference in academic papers and memos? How does it affect the tone and structure of the two papers? Im stuggling with this assignment. Please help.
March 6, 2010

statistics
Assume that Acme Tires sells their high performance tires for $180 each and their all weather tires for $135 each. Further assume that the cost of producing a high performance tire is $150 and the cost of producing an all weather tire is $120. Finally, assume that if a tire ...
March 6, 2010

statistics
What is the expected value (expected profit) of producing an all weather tire?
March 6, 2010

math
how do u do two step equations
March 4, 2010

Chemistry
Balance the following equation: C6H5COOH + O2 ==> H2O + CO2
March 3, 2010

chemistry
Phosphoric acid and barium hydroxide solutions mix to form water and solid barium phosphate. Write the word equation, skeletal equation, and the balanced equation for this word problem.
March 3, 2010

chemistry
for the second part do i subtract 100-75 = 25 = -(the constant)(time)
March 3, 2010

chemistry
So its Ln ( 50/100) = k (34 min)?
March 3, 2010

chemistry
A reaction is 50% complete in 34.0 min. 1.) How long after its start will the reaction be 75% complete if it is first order? 2.)How long after its start will the reaction be 75% complete if it is zero order? steps would be helpful
March 3, 2010

Math - Algebra
This is a fraction algebra. n/24=25 (not divide sign). I don't know if I have to multifly and which number do i use.
March 2, 2010

chemistry
Do I use the t(1/2) = ln2 / K formula? In that case...would I just substitute any of the data that I want? Like t(1/2) = 0.715, ln2, then find k?
February 28, 2010

chemistry
For the reaction A to products}, the following data were obtained: t=0 s, A}]=0.715 M; 22 s, 0.605 M; 74 s, 0.345 M; 132 s, 0.055 M. What is the half-life of the reaction? ive been posting this for awhile now...can someone just show me how to go about doing this problem? i ...
February 28, 2010

chemistry
For the reaction A to products}, the following data were obtained: t=0 s, A}]=0.715 M; 22 s, 0.605 M; 74 s, 0.345 M; 132 s, 0.055 M. What is the half-life of the reaction?
February 28, 2010

chemistry
For the reaction A to products}, the following data were obtained: t=0 s, A}]=0.715 M; 22 s, 0.605 M; 74 s, 0.345 M; 132 s, 0.055 M. What is the half-life of the reaction?
February 28, 2010

chemistry
for this one do i just plug in k A^2B^0 = rate?
February 28, 2010

chemistry
The reaction A + B to C + D is second order in A and zero order in B. The value of k is 1.10×10−2 M^{-1}\;min^{-1}. What is the rate of this reaction when A}]=0.124 M and B}]=3.89 M?
February 28, 2010

Chem- follow up question
Sorry i posted this as an answer after my question had been answered, this is continued from the qualitative analysis question: That reallly cleared some things up, but I do still have a few questions. Umm im not completely clear on the hyrogen peroxide subject. its added to a...
February 28, 2010

Chemistry
That reallly cleared some things up, but I do still have a few questions. Umm im not completely clear on the hyrogen peroxide subject. its added to a solution containing aluminum chloride and iron chloride, and you said it is ther eto make sure the ion is Al3+, can you please ...
February 28, 2010

Chemistry
HI, we conducted a qualitative analysis, to identify the cations in an unknown sollution..trying to determine whether it had Al 3+, Fe (3), and Lead ions..i am having trouble understanding some parts of the procedure. before testing for aluminum and iron, hydrogen peroxide was...
February 28, 2010

chemistry
For the reaction A to products}, the following data were obtained: t=0 s, A}]=0.715 M; 22 s, 0.605 M; 74 s, 0.345 M; 132 s, 0.055 M. What is the half-life of the reaction?
February 28, 2010

chemistry
The reaction A + B to C + D is second order in A and zero order in B. The value of k is 1.10×10−2 M^{-1}\;min^{-1}. What is the rate of this reaction when A}]=0.124 M and B}]=3.89 M?
February 28, 2010

chemistry
The reaction A to products is first order in A. 1.) If 2.00 g A is allowed to decompose for 42 min, the mass of A remaining undecomposed is found to be 0.50 g. What is the half-life, t_{1/2}, of this reaction? 2.)Starting with 2.00 g A, what is the mass of A remaining ...
February 28, 2010

Art
Does anyone know what the difference between analytical and expressive lines are and where I can find some art examples of each?
February 26, 2010

physics
0.490 mol of argon gas is admitted to an evacuated 50.0 cm^3 container at 60.0 C. The gas then undergoes an isochoric heating to a temperature of 400 C. What is the pressure?
February 26, 2010

Accounting
Given the data, would you have invested in Quality Department Store in 2006? Explain why or why not. Summarize your analysis of the financial data to support your reasoning. What recommendations would you make to improve the financial health of this company? Explain why.
February 24, 2010

physics
If 2.0J of work is done in raising a 180g apple, how far is it lifted?
February 21, 2010

Crt/205 Critical Thinking
I need help with this assignment: Argument Evaluation DUE: Day 7 Points: 100 · Read the essay “Bush’s Environmental Record” by Bob Herbert found in the “Appendix 1”, pgs. 461-462. To find this, click on the “Controlling Irrational Fears ...
February 21, 2010

algebra
5 yrs ago Montys age was 5 years less than twice Rachels age. In 3 years, one third of Rachels age will be 12 years less than Montys age. How old are they now?
February 18, 2010

math
No - that comes out to a negative number - doesnt it? Can you show the next steps?? I am not sure why it is not coming out -
February 18, 2010

math
5 yrs ago Montys age was 5 years less than twice Rachels age. In 3 years, one third of Rachels age will be 12 years less than Montys age. How old are they now?
February 18, 2010

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