# Posts by dave

Total # Posts: 866

**math**

Having trouble with these pairs of numbers (20,21,29) - (28,45,53) I am supposed to develop a Pythagorean triple. Here is that I am supposed to use which is a formula that can be used to generate infinite number of generating Pythagorean triples is: a = (2mn); b= (m^2 - n^2...

**math**

Could someone please describe two main differences between classical and empirical probabilities.

**math**

I do not know how to answer this question. Would someone please help me with each of the four question below? Thank you. Question 1. Write the sample space for the outcomes of tossing three coins using H for heads and T for tails. Question 2. What is the probability for each ...

**math**

This is what I am trying to solve for - x2 – 2x – 13 = 0 - x2 - 2x = 13 step (a): move the constant term to right side of the equation 4x2- 8x = 52 step (b): multiply each term of the equation by 4 times the coefficient of x2 – in this case 1x4 = 4 (trying to ...

**math**

In this equation 4(x^2 – 8x) = 4(13), what would the coefficient of x^2 be in this case? Would this be correct 4x1=4? If not, what would the correct answer be?

**math**

My problem I have involves a method that requires using the quadratic equations that comes from India. Here the problem that I have to solve : x to the second power plus 12x minus 64 equals 0 I need someone to walk me through each step to arrived to the answer for this problem...

**Math**

Can someone please help me to answer the following question? The question below has four choices, but only one correct answer. Could you please help me with the correct answer for this question? Thank you in advance. Question # 1. Find the slope of the line passing through the...

**Diffeq**

d/dx (x)(e^xy)(cos2x). Product rule lets me take the derivative of f(x)g(x). But three functions?

**Math**

Please Help! (R=restaurant) If R1 is 480-8t-0.8t^2 and R2 is 254+0.78t, how would I write a function (R3)that represents the total sales for the the two restaurants?

**PreCalculus**

(R=restaurant) If R1 is 480-8t-0.8t^2 and R2 is 254+0.78t, how would I write a function (R3)that represents the total sales for the the two restaurants?

**maths**

if two sides must be parallel then the fourth side is also 3.5 cm add the sides = perimeter

**English**

I would shy away from first person unless specifically to write from that perspective.

**maths**

1km = 1000 m 100cm = 1 m convert to meters and divide

**math**

check out law of cosines

**chemistry**

Fish-liver oil is a good source of Vitamin A. When 0.1232 g of fish liver oil is dissolved in 500. mL of solvent, an absorbance of 0.724 is recorded. When 0.00167 g of Vitamin A is dissolved in 250. mL of solvent, an absorbance of 1.018 is recorded. Calculate the mass percent ...

**Math**

The additive inverse is the # which when added to a number equals zero. If you consider 12 on the clock to be '0", the -3 and 9 would both have 3 as an "AI"

**Physics**

Thanks, I couldn't find an equation that derives the max velocity of the pendulum in my textbook.

**Physics**

Find the speed of a pendulum bob at the bottom of its swing if its initial displacement is 5 degrees and its period is 2 s.

**Physics**

Thanks. I was confused by the way the question was worded and my answer was 2 times bigger than what the answer is supposed to be.

**Physics**

A child of mass 40.0 kg is swinging on a swing with ropes of length 4.0 m. How long does it take the child to swing from the maximum height on one side to the other?

**Science**

equal, opposite

**Social Studies (geography)**

do a search for maps of the world / lat /long

**Math**

replace n with inf. 1 + (-1^0/0) = 1 +(-1^0) = 1+1= 2

**Math**

The additive inverse is the # which when added to a number equals zero. interesting questions. If you consider 12 on the clock to be '0", the -3 would have 3 as an "AI". If you consider the number you are starting from to be "0" then = or - 12 ...

**STATISTICS**

The experiment was not 'double blind" because the same person who compared the test scores (the professor) was aware of the reason for the experiment. If the groups were aware of the reason for them playing the games (possible affect on test scores) this would be ...

**algebra**

for every increase of 1 in x, y decreeases by 3 this gives us 3x y=0=23 so, y=23-3x

**chemistry**

ahh, of course, thank you.

**chemistry**

Consider a red flame color produced by excited lithium with a wavelength of 671 nm. What is the mass equivalent of 1 mol of photons of this wavelength? I can get as far as Js of E Can't seem to find equation to turn Js into mols, or photons into mols, for Js into photons. ...

**Algebra**

1 * 10^-3 = .001 1 * 10^-4 = .0001 1 * 10^-5 = .00001 Get the Idea?

**science**

what would happen if you mixed isopropanol with copper and dranked it

**Calculus**

y-(-4)= 5/2(x-3)-b this should be slope intercept FORM of what you wrote.

**chemistry**

what would happen if you mixed isopropanol with copper

**Math 156**

an infinity of shapes can have two right angles provided they have more than three sides and the sum of the inside facing angles minus the sum of the outside facing angles equals 180 degrees.

**chemistry**

h*c/lambda would this be planck's constant times speed of light / wavelength?

**chemistry**

An electron in the n = 5 excited state of a hydrogen atom emits a photon of 1281 nm light. To what energy level does the electron move? Any ideas on an equation for this? Is it some kind of backward version of Rydburg Eq?

**MATH**

correct. can be written as just 9s^2 - 4d^2

**MATH**

let x be ttl $ spent (2.75 * days) y=110-x

**Math**

You have two problems here. 1. need D:f(x) = 2sqrtx 2. subsitute x=4 into derivative D: 2sqrtx : a) multiply power times coefficient; 1/2 * 2 = 1 b)power - 1 = 1/2 -1 = -1/2 c. f'(x) = x^-1/2 or 1/sqrtx substitute 4 for x and you should be there

**math**

yup

**physics**

blocks A and B weigh 10 lb and 40 lb, respectively. A and B extend over a fixed drum, one on reach side. Determine the acceleration of A and the tension in the cord if the fixed drum is smooth.

**Math**

If a cube has one edge of 2m, what is the surface area of this cube?

**chemistry**

The heat of vaporization of a substance is 2900 J/g at its boiling point of 313C. How much of this substance can be vaporized if 58700 J of energy are available?

**Math**

What is the sum of the measures of the interior angles of an 11-side polygon?

**Geometry**

If ∆ ABC ~ ∆ DEF, BC = 12 cm, EF = 10 cm, and AC = 18 cm, find DF.

**business**

Your manager has asked that you reach out to three senior leaders in the organization to build a better understanding of their needs so that your department can better align themselves with these executives’ and build partnerships for new work. Where will you look for ...

**earth**

What does the word anti mean? My answer- is opposed to something????? Please help me

**chemistry**

I ALSO NEED HELP

**Physics - bungee jumping**

The gravitational potential energy of the jumper is mgh, where m is 60kg and h is 22m - 1.8m or 20.2m. The PE of the bungee at full length is 1/2kx^2, where x is the difference between stretched and unstretched length, i.e. 20.2m - 12.2m or 8m. Setting these to equal: 1/2kx^2=...

**Math/Statistics**

The mean starting salary for graduates in the spring of 2004 was $36,280. Assume that the distribution of starting salaries follows the normal distribution with a standard deviation of $3,300. What percent of the graduates have starting salaries between $35,000 and $40,000? a...

**Math**

Solve the equation- e^x2+5x+6=1

**statistics**

1. Test the Nation on CBC:“Test the Nation” was the biggest survey ever conducted to see just how smart Canadians are. In this live two-hour special, 1.5 million Canadians participated in a real-time interactive IQ test. Viewers took the test in the comfort of their ...

**Trigonometry**

You observe a plane approaching overhead and assume that its speed is 700 miles per hour. The angle of elevation of the plane is 16° at one time and 58° one minute later. Approximate the altitude of the plane

**Physics**

You weigh 585N on Earth, what is your mass? What do you weigh on the moon id g is 1.60m/s2

**st elizabeth technical**

1. What would you think of a company's ethics if ti changed accounting methods every year? 2. What accounting principle would changing methods every year violate? 3. Who can be harmed when a company changes its accounting methods too often? How?

**World History**

farming

**chemistry**

(1)acid+base=.1M potassium dibasic phosphate: 7=12.67 + log(base/acid) (base/acid)=2.138x10^-6 subst. in (1) base+base/2.138x10^-6=.1 solving base=2.13x10^-7M Mass of base=2.13x10^-7 x (174.18g)=3.71x10^-5g Now I can find the mass of the acid as well by substituting for the ...

**chemistry**

I should have given more info. I figured that I would use the H-H equation and the total conc., but what I don't get is why do I need two pka's. I can get to the mass easily, but it seems that I could use either pka=7.21 or 12.67 with the base +acid =.1M.

**chemistry**

Calculate the mass of salts needed for constructing a buffer using potassium monobasic phosphate and potassium dibasic phosphate with the total concentration of 100 mM. The solution is to be prepared in DI water and the pKa value for potassium monobasic phosphate is 7.21 and ...

**geometry**

what are the possible coordinate of the midpoint of the given segment

**algebra**

factors

**Algerbra**

10,000(1-n/20)=6500 please show work

**english**

8. In Frost’s poem “Mending Wall,” the lines “I see him there, / Bringing a stone grasped firmly by the top / In each hand, like an old-stone savage armed” uses which poetic device?

**math**

log8 4(square root sign) 1/2

**Math**

you werent supposed to include the 1-

**Math**

Write the following logarithmic equation in exponential form? 1- log0.001 = -3

**math**

thank you

**math**

a baseball team buys 15 bats for $405. aluminum bats cost $25 and wooden bats cost $30. how many of each type did they buy? Please show work

**6th grade**

Your stupid...

**Chem.**

Acetic acid (CH3COOH) reacts with isopentyl alcohol (C5H12O) to form isopentyl acetate (C7H14O2), a fragrant substance with the odor of bananas. CH3COOH + C5H12O -> C7H14O2 + H2O If the yield for the reaction is 45%, how many grams of the product are formed when 3.58 g of ...

**Chem**

Acetic acid (CH3COOH) reacts with isopentyl alcohol (C5H12O) to form isopentyl acetate (C7H14O2), a fragrant substance with the odor of bananas. CH3COOH + C5H12O -> C7H14O2 + H2O If the yield for the reaction is 45%, how many grams of the product are formed when 3.58 g of ...

**Chemistry**

A 2.50 gram sample of bronze was dissolved in sulfuric acid. The copper in the sample reacted with sulfuric acid to form copper sulfate. Cu (s) +2 H2SO4 (aq) -> CuSO4 (aq) +2 H2O (l) The copper sulfate formed in this reaction was mixed with I to form copper iodide: CuSO4 (...

**math**

A tugboat can go 10 miles upstream in the same time as it can go 15 miles downstream. If the tugboat goes 12 miles per hour in still water, what is the speed of the current?

**algebra**

While shopping, Jill spent six times as much as Nan. If they spent a total of $112, how much did each person spend?

**physics**

actually the other guy has it right except that he has sin instead of cosine

**physics**

Thank you. I figure out the answer for this one. I do have another one.

**physics**

A large boulder is ejected vertically upward from a volcano with an initial speed of 41.0 . Air resistance may be ignored.

**physics**

Hi: I need help with the following physics problem. Can you explain it to me? Thank you, The fastest measured pitched baseball left the pitcher's hand at a speed of 50.0 . If the pitcher was in contact with the ball over a distance of 1.50 and produced constant ...

**physics**

Hi: I need help with the following physics problem. Can you explain it to me? Thank you, The fastest measured pitched baseball left the pitcher's hand at a speed of 50.0 . If the pitcher was in contact with the ball over a distance of 1.50 and produced constant ...

**Math**

Reduce each rational expression x^3-4xy^2/3x^3-2x^2y-8xy^2

**5th grade math**

A marathon race has 522 runners divided into 6 groups. What is a reasonable number of runners in each group? A 112, because 522/6 is about 550/5=110 B 98, because 522/6 is about 500/5=100 C 87, because 522/6is about 540/6=90 D 82, because 522/6 is about 480/6=80

**algebra**

find function value f(x)=x

**CHEM**

the pressure and temp being constant, you would add 8.00g of helium to the 8.00g to double its volume. If pressure or temp were varied this would not be true.

**vector proofs math 536**

*******Prove that AM/BM = MC/MD

**vector proofs math 536**

if the diagonals of quadrilateral ABCD intersect at their midpoints, then the quadrilateral is a parallelogram. Prove that AM MC --- = --- MB MD Ive tried figuring out this question for a while now and I cant figure it out.

**physics**

really stuck, a 90 kg skier has 140 KJ of total mechanical energy when he is at a height of 120m above the bottom of the hill. calculate the skiers kinetic energy. calculate his speed?

**8th grade**

Poooop

**Finance(trying to dichper)**

How would you read these two formulas? The 1/4 and 1/6 are throwing me off. These are example problems from what I need to do. Variance=1/4[(0.03 – 0.1)2 + (–0.14 – 0.1)2 + (0.27 – 0.1)2 + (0.22 – 0.1)2 + (0.12 – 0.1)2] Geometric average return...

**General Chemistry**

A student dissolved 4.00 g of Co(NO3)2 in enough water to make 100. mL of stock solution. He took 4.00 mL of the stock solution and then diluted it with water to give 275. mL of a final solution. How many grams of NO3- ion are there in the final solution? 0.0197 g 0.0394 g 0....

**Chemistry**

Why do Oxygenated fuels contain less energy than hydrocarbons?

**chem**

Why do oxygenated fuels contain less energy than hydrocarbons?

**Science**

If the acceleration gravity is 1.6m/2 on the moon and you weigh 539 N on earth, how much do weigh on the moon?

**science**

D.

**calculus**

a right circular cylinder has a volume 600cubic cm. if it costs $2 for the material needed to make the top and bottom and $3 for the material needed to make the sides, what is the radius and height of the cylinder that would cost the least?

**chemistry**

For which of these elements would the electron affinity process shown be least favorable? 1. H + e− ! H− 2. Li + e− ! Li− 3. F + e− ! F− 4. O + e− ! O− 5. N + e− ! N−

**chemistry**

The first ionization potential of the elements B, C, and N (atomic numbers 5, 6, and 7) steadily increases, but that of O is less than that of N. The best interpretation of the lower value for O is that: 1. the ionization potential of N is a maximum and the values decrease ...

**chemistry**

For which of these elements would the electron affinity process shown be least favorable? 1. H + e− ! H− 2. Li + e− ! Li− 3. F + e− ! F− 4. O + e− ! O− 5. N + e− ! N−

**chemistry**

That weird symbol was supposed to be quantum number l.

**chemistry**

In an atom, the maximum number of electrons having the quantum numbers n=5 and §¤ = 3 is: 1. 9. 2. 14. 3. 50. 4. 25. 5. 7. Shouldn't the maximum number be a lot bigger than the answer choices?

**12th Grade Maths**

simplify (e is positive) (24e)^1/3 / (3e)^1/3

**college Macroeconomics**

All would increase due to economic growth and the shiftward of all curves rightward. Price level will be ambiguous.