Thursday
August 27, 2015

Posts by David


Total # Posts: 1,810

Alg/Trig
(x-2)^2 + (y-3)^2 = 4.5^2
July 6, 2012

math ( pre algebra )
B. H
July 6, 2012

math
nonsense. let the three batteries by A,B,C then A = 2B 3A = C A + B + C = 54 so A = 12 B = 6 C = 36
July 6, 2012

math
How do I take the partial derivative of P with respect to r of the following: D × P = ∑(t=1 to T)[t × (CF)_t/(1+r)^t ]
July 6, 2012

Algebra 2
Thanks Ms Sue its my daughters problem ,my responce was maybe the wording might be asking "what investment " might be what amounts in what types of investments would yield the $4ooo. Or it might be just be about the math and analizing it. Either way ,thank you
June 5, 2012

Algebra 2
As a graduation present, you want to gift your son a trip to Disney World. Presently beginning his second semester as a high school junior, you hope you have enough time to save $4,000 to support much of the trips expenses for your child and two of his closest friends. Rather ...
June 5, 2012

english/grammar
I need help editing errors in parallelism in the following sentence: Is it true that Superman could leap tall buildings, run faster than a locomotive, and that bullets would bounce off his skin?
June 2, 2012

grammar
ops whats the first one
May 14, 2012

grammar
Whats the last one?
May 14, 2012

physics
or I've kept up with my homework and work this whole year except that our teacher just randomly decided to give us a ton of homework this weekend, and I have done all I can do. All of my friends are in the physics 1 class while this is physics 2 so no I cannot have answers...
May 13, 2012

physics
Hi, my teacher doesn't teach us too well and we have a few packets to hand in for tomorrow that I really don't understand much of. If someone could give me the answers to all of the problems on the first link if you search "the electrical energy converted to ...
May 13, 2012

Geometry word problem
A rectangular pond is 10m longer than it is wide. A walk 2m wide surrounds the pond. Find the dimensions of the pond if the area of the walk is 216m2
May 9, 2012

Geometry
A rectangualar playground is 4 meters longer than it is wide. If the length is increased by 5m, and the width decreased b y 1 m, the area is increased by 15m SQUARED(15M2).Find the original dimensions of the playground.
May 9, 2012

Math
How do i solve 2x+y > -3? And how do i graph it. This is Linear inequalities.
May 3, 2012

phisycal sciences
Which of the following properties did Rutherford use in his experiment? A. the negative charge of the alpha particles and the random distribution of protons B. the negative charge of the alpha particles and the positive charge of the gold foil C. the positive charge of the ...
May 3, 2012

Mathematics
Two numbers have thousandths other than zero. Could the difference of these numbers be 5.3? Explain.
May 2, 2012

algebra 2
Write an equation for a parabola with vertex at (3,- 6) and focus at (3,- 4).
May 2, 2012

chemistry
Is beta particles the answer?
April 30, 2012

chemistry
Which radioactive emanations have a charge of -1? beta particles alpha particles gamma rays neutrons
April 30, 2012

Algebra
-4x+1-2(x-1)= -4(x-4)
April 29, 2012

algebra
Write an equation of the hyperbola with foci (0, ) and (0, 2) and vertices of (0, ) and (0, 1).
April 29, 2012

spanish
Escribe el cual (la cual, los cuales, las cuales) o lo cual en el espacio. Nos invitaron a cenar con ellos, ____ fue una buena idea.
April 29, 2012

spanish
¿Cuál frase es correcta? El hijo del maestro, quien estuvo en mi clase, es muy inteligente. El hijo del maestro, a quien estuvo en mi clase, es muy inteligente.
April 29, 2012

algebra
When you spend $1 at the grocery store, the store doesn’t keep all of your money as profit. Some of it is reinvested in the economy when the grocery store buys more merchandise from suppliers. In turn, the suppliers don’t keep all of that money as profit, either; ...
April 28, 2012

Finance
Calculate the weighted cost of equity for a firm with the following characteristics: (a) Last Dividend--$5.00, (b) Growth Rate—6%, (c) Price of Stock--$125.00 and (d) Weight of Equity Capital—40%
April 27, 2012

English
Help me to write these answer question, Write an essay that illustrate the saying every cloud has a silver lining in 340 words
April 27, 2012

American Lit.
What is Fundamentalist-Modernist Controversy.? Is this one whole topic or more than one.?
April 24, 2012

computer programming
Make an Maplet that does the simple calculator funtions as addition, subtraction, multiplication, division, factorial, sin(), cos(), tan(). (using maplet in maplesoft)
April 22, 2012

physics
a one meter chain that weights one newton sits on a flat horizontal table that is one meter from the floor. the coefficient of friction between the chain and the table is 0.15. how much of the chain can dangle off the table until the chain pulls itself onto the floor? if it ...
April 20, 2012

College Algebra
log5 (x+2)+log5(x-2)=3
April 20, 2012

algebra
2(2x+5)-7<12 2(2(-5)+5)-7<12 2(-10+5)-7<12 2(-5)-7<12 -10-7<12 -17<12
April 16, 2012

geometry
A circle of radius r is centered at the origin and a rectangle is inscribed. The area of the rectangle as a function is given by what? Can you also explain the processes behind finding the answer it helps me understand.
April 15, 2012

Environmental Science
7 is D 10 is probably B because mosses are the first thing to grow naturally after the destruction of an environment like building a building 21 is D the y all effect marine ecosystems and are caused by humans 27 is D
April 15, 2012

Chemistry
Calculate the Concentration of Ni2+ in a soltion which prepared as mixing 50.0ml 0.0300 M Ni2+ and 50.0mlml 0.0500 M EDTA at pH= 3 At pH=3 , α4= 2.5x10-11 KNiY=4.2x1018
April 15, 2012

Chemistry
calculate the the pH of a buffer solution containing 0.246 M NH3 and 0.0954 M NH4Cl (for NH3 Kb = 1.74x 10-5)
April 15, 2012

Chemistry
what mass of AgBr is formed when a solution containing 3.45 g of KBr is mixed with a solution containing 7.28 g AgNO3?
April 14, 2012

chemistry
You have a 1 L container of a gas O 2 at 20°C and 1 atm. Subtracting the weight of the container, what is the mass of the gas?
April 6, 2012

physics
A truck covers m in 8 s while smoothly slowing down to a final speed of 2.8 m/s. (a) Find its initial speed. (b) Find its acceleration.
April 5, 2012

Chemistry
How many grams of water are formed when 250 mL of 2.0 M Mg(OH)2 are neutralized by a solution of HCL ?
March 23, 2012

Chemistry
How many mL of 3.0 M HCL are required to neutralize 250 mL of 2.0 M MgCL2 ?
March 23, 2012

MaTh AlgeBRA
Do synthetic division or long division Domain is all reals except x=1 because it gives you a 0 denominator.
March 22, 2012

Calculus
Let (3,1,-2) = C A+B=C B=C-A B=C+(-A) Do the addition component by component.
March 22, 2012

Chemistry
Both compounds are soluble, thus you have a double replacement reaction. Do stochiometry with the balanced reaction to find the concentrations.
March 22, 2012

Physics
Because of the symmetry in the path of a projectile, it will return to your hand with a speed of 40 m/s downward. Its total displacement is 0 since it returns to starting position. To find the distance traveled, multiply the height it reaches by 2. Find the height using ...
March 22, 2012

Physics
Assuming the angle of the throw was perfectly horizontal, x=v0*t=10*4=40m
March 22, 2012

physics
x=Vo*t since no forces act on the car in the x direction. Solve for t, t = x/v0^2 y=Vo*t+at^2/2 in this case, y = h, Vo in the y direction is 0, a = -g and use the relationship from before. Substitute solve for Vo^2 and your all done
March 22, 2012

math
x+x+3=57
March 22, 2012

Algebra II
x1/y1=x2/y2
March 22, 2012

conics
slope of PO= y/x slope of PN = y/(x-12) For segments to be perpendicular their slopes must be negative recipricols Thus, -x/y=y/(x-12) y^2+x(x-12)=0 Distribute the x, complete the square, and then you'll have the equation of a circle.
March 22, 2012

math
Draw a quadrangle below.Measure the sides to the nearest 1/2 inch.Write the length next to each side.Find the perimeter.
March 22, 2012

physics
Howstuffworks has a pretty thorough yet comprehensible explanation. I'd check that out.
March 21, 2012

CHEM
if something has a pH of 3.72 its not a base... did you mean pOH?
March 21, 2012

physics
T is period so you have frequency and period backwards
March 21, 2012

physics
use the formula T = 2*pi*sqrt(L/g) make sure you use SI units.
March 21, 2012

physics
Use the relationships 1 watt = 1 Joule / second E = mc^2 E = energy, m = mass, c = speed of light (3*10^8 m/s)
March 21, 2012

physics
you need to know that relationship that in that form, w = 2*pi*frequency thus w = 2*pi*525 2)cycles per 1 minute = 60 seconds *frequency = 60 * 535
March 21, 2012

math
13*3=39
March 21, 2012

math
6*10 + 10*(1/2) = 65
March 21, 2012

trig
Cosine is 0 at pi/2 3pi/4*t=pi/2 t=2/3
March 21, 2012

physics
w = 2*pi*period
March 21, 2012

physics
nevermind I thought it said that it began at its highest point. Since they didn't specify any initial conditions you're free to use either sin or cosine with no phase shift.
March 21, 2012

physics
It doesn't make a difference as long as your value for when t = 0 is correct since sin is just cosine phase shifted by pi/2. Cosine is probably easier in this case because then you wont need to do a shift.
March 21, 2012

physics
Period = time per cycle = 15 seconds frequency = 1 / period = 1/15 hz amplitude= 3 ft because its actually the distance from the center to each side. from there just put it into standard form.
March 21, 2012

Chemistry
It depends on the indicator. At the equivalence point, hypothetically they are equal. Most indicators however do not change color at exactly 7 and thus pH of the endpoint determines the concentrations of H+ and OH-
March 21, 2012

Physics
If the bus is moving with constant velocity, there's no net force on the bus, and thus you don't need to compensate for the bus's motion. If the bus is moving forward with constant acceleration, there will be a force pushing the bus forward, however from inertia ...
March 21, 2012

math
total time = 4 hours + 3 hours = 7 hours. Avg speed = total distance / total time Avg speed = 40 * 2 / 7 = 80/7 km/h
March 20, 2012

math
total distance = 526 + 5 * 70 avg speed = total distance / 12 min
March 20, 2012

science
Pv=nRT for both the initial and final state. Only thing your changing are temperature and since moles, R and volume are constant pressure must change. Thus P1/T1=P2/T2 P2=P1*T2/T1
March 20, 2012

Calculus
Volume=s^2*h=32 Surface area = s^2 + 4*s*h using volume equation, h=32/s^2 SA= s^2 + 4*s*(32/s^2) = s^2 + 128/s Take derivative dSA/ds and set equal to zero. 2s - 128/s^2 = 0 s^3 = 64 s = 4
March 20, 2012

Economics
D Rule 1 of microeconomics The optimal quantity for essentially everything is where marginal revenue = marginal cost
March 20, 2012

Physics
sum of forces vertical = 0 = mg - Ncos@ sum of forces horizontal = mv^2/r = Nsin@
March 20, 2012

math
to divide by a polynomial with power other than 1 you have to use long divison. However for this problem that's not necessary... just factor G(x) = (x-2)(x-3)/(x-3)(x+3) thus your only zero is x = 2 since the function is not defined at x = 3
March 20, 2012

Chemistry
Explain why the absolute values of the standard enthalpy change in the reaction and heat measured by the calorimeter are not equal. Assume that there are no measurement errors of any kind. In the previous problem I solved that Delta H rxn was -1500 and q = 1.519 x 10^6 J and I...
March 17, 2012

Chemistry
For the following reaction, the equilibrium constant Kc = 97.0 at 900K. If the initial concentrations of NH3 and H2S are both 0.20 M, what is the equilibrium concentration of H2S? H2S(g) + NH3(g) = NH4HS(s) Would you have to create an ICE chart for this type of problem?
March 17, 2012

Chemistry
The equilibrium constant Kp for the following reaction is 4 atm^2 at 300 K. AB(s) = A(g) + B(g) What is the equilibrium pressure of A(g) and B(g) above AB(s) at 300K? What is Kc at 300K? How would i solve this when they don't even give me any partial pressures?! All of the...
March 17, 2012

Chemistry
oh wow........ :[ thanks Dr. Bob
March 17, 2012

Chemistry
Which of the following statements are incorrect? 1) Gases are not included in the equilibrium constant expression. 2) Equilibrium constant can be increased by adding a catalyst 3) Large equilibrium constant favors reactants 4) Equilibrium is typically achieved in a very short ...
March 17, 2012

algebra
describe the number tha make the statement true: 3-16>23
March 17, 2012

Chemistry
The equilibrium constant Kc for the following reaction is equal to 0.20 at 250°C. Calculate the equilibrium constant Kp for the reverse reaction at the same temperature. COCl2 (g) = CO (g) + Cl2 (g) I'm sorry.. English is a second language for me. After solving for K&#...
March 15, 2012

english
Identify the capitalized part of speech in the following sentence: You should be proud of him, FOR he's a "jolly good fellow." Answer a. noun b. pronoun c. verb d. adjective e. adverb f. preposition g. conjunction .
March 14, 2012

physics
A simple pendulum has a mass m and carries a charge q. The pendulum is suspended between the vertical plates of a capacitor of separation distance d. If the string of the pendulum makes an angle θ with the vertical, what is the potential difference between the plates
March 13, 2012

physics
A simple pendulum has a mass m and carries a charge q. The pendulum is suspended between the vertical plates of a capacitor of separation distance d. If the string of the pendulum makes an angle θ with the vertical, what is the potential difference between the plates
March 13, 2012

math
Having difficulty with the four frequency ,to use in a table and determine and find the range ..im not understanding whays needed ?
March 12, 2012

physics
A simple pendulum has a mass m and carries a charge q. The pendulum is suspended between the vertical plates of a capacitor of separation distance d. If the string of the pendulum makes an angle θ with the vertical, what is the potential difference between the plates
March 12, 2012

english
Identify the subjects of the following sentences. Jacob's favorite poker game is Texas Hold'em
March 8, 2012

Art
What are the six architectural features of the Chartres Cathedral?
March 8, 2012

Chemistry
why does the equil end up being 0.8-x instead of 0.8 - 2x? and i solved for x but it gave me 2 different answers did I do something wrong?
March 5, 2012

Chemistry
the extra NO being added threw me off.. or is it supposed to be like Kc = 0.800M^2/[0.100M][0.100M] = 64 M?
March 5, 2012

Chemistry
At equilibrium, the concentrations in this system were found to be [N2] = [O2] = 0.100 M and [NO] = 0.500 M. N2(g) + O2(g) <-> 2NO(g) If more NO is added, bringing its concentration to 0.800 M, what will the final concentration of NO be after equilibrium is re-...
March 5, 2012

Calculus implicit
4sin(x-y)*d(x-y)=3y' + 3ycosx On the left I applied the chain rule, and on the right i used the product rule. 4sin(x-y)*(1-y')=3y' + 3ycosx Differentiate x - y and get 1 - y' Then do algebra to solve for y' 4sin(x-y) - y'*4sin(x-y) = 3y' + 3ycosx 3y...
February 29, 2012

physics
At the top of the loop mv^2/R=mg+N However if we ant minimum speed put N to zero. Thus to stay in the loop mv^2/R=mg v at the top thus = sqrt(g/R) To get to the top of the loop you are at a height of 2R, so the amount of energy lost getting there is 2mgR. Thus the initial ...
February 29, 2012

physics
I'm going to assume the diagram gives the tension in the string, because with what you stated you're missing a degree of freedom. Only two equations can be developed (Sum of forces = 0 in both the x and y direction). However, we're missing the tension's ...
February 29, 2012

chemistry
pH = -log[H+] = -log(.0019) Since HNO3 breaks into H+ and NO3- with a 1:1 ratio. Also log is base 10.
February 29, 2012

Elementary statistics
The total number of outcomes is 9C3, because there are nine apples and you are choosing 3 where order doesn't matter. P(0) = 5C3 / 9C3 because there are 5 good apples and you need to choose 3. P(1) = 5C2*4C1 / 9C3 P(2) = 5C1*4C2 / 9C3 P(3) = 5C0*4C3 / 9C3
February 29, 2012

Calculus-derivatives
Set the derivative equal to zero.
February 29, 2012

physics
Use the kinematic equation V = V0 + at defining up as positive. Thus, t = (V-V0)/a V0 is given as 100 m/s At the top of the path V = 0 a = -9.81 m/s^2 (gravity) Thus, t is about 10 seconds
February 29, 2012

math
27+6=33 need to regroup Yes or no
February 28, 2012

college algebra
a) x will be the width of the rectangle, and y will be the height. A = x*y = x(-1/2x+4) b) plug in x = 1, 2... 7 c) [0,8] because that's where the function crosses the x and y axis
February 28, 2012

college algebra
you have two points (32000,98000) and (35000,117500) Find the slope (117500-98000)/(35000-32000) put into point slope form y-y0=m(x-x0) using one of the two points for x0 and y0. b) Plug in x as 50,000 and solve for y. c) plug in y as 0 and solve for x
February 28, 2012

math
There are two poles. One is 60 feet tall and the other is 8 feet tall. they are 60 feet apart. How much wire would you need to connect the two poles?
February 27, 2012

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