# Posts by Rob

Total # Posts: 401

**science**

which of the following is formed from molten rock that contains large amounts of gasses?? A: Rhyolite B: granite C:basalt D: pumice

**Algebra**

How do I do radical 7/10... my answer was 4 radical 3 over 6... is that correct?

**MATH**

24 pages

**College Chemistry**

[H30+] = 10^-(pH goes here) A log is an exponent. Since pH is a negative log, it's an exponent with a negative sign on it (with an implied base of 10).

**Econ**

In which of the following circumstances would a buyer be indifferent about buying a good? a. The amount of consumer surplus the buyer would experience as a result of buying the good is zero. b. The price of the good is equal to the buyer's willingness to pay for the good. ...

**Econ**

A result of welfare economics is that the equilibrium price of a product is considered to be the best price because it a. maximizes total revenue for firms and maximizes the quantity supplied of the product. b. maximizes the combined welfare of buyers and sellers. c. minimizes...

**science**

what do the tropic of capricon, tropic of cancer lines, artic, an antartic circles represent?

**science**

how were the latitudes of the tropic of cancer, tropic of capricorn, Arctic circle, and Antarctic circle determined?

**science**

heyy my friend rob needs help can u help him too?

**math**

Given: They collected 49 + 72 + 108 + 121 = 350 lbs of cans. So, the KNOWN part of the question is, “These folks collected 350 lbs of cans.” Answer: 10 I say the answer, 10, is really, “10 cents per pound.” Therefore, the UNKNOWN part of the question is, &#...

**4th grade math**

Sixty-five hundredTHs is 0.65 (0.065 would be sixty-five thousandths).

**rehabilitation**

under what circumstances is it easy to turn your will and life over to the care of god

**Algebra**

I have to solve the following equation: x+y=9 xy=54 I changed the first equation to y=9-x to solve for y. I got x(9-x)=54 and then 9x-x^2=54. I then changed 9x-x^2= 54 to -x^2 +9x-54=0. I got stuck around here, can someone explain...

**math**

hi i was wondering how would you find the equation of a parabola with it's vertex at -2,0, and with no directrix or focus given. the parobala opens toward the left. the two choices in my multiple choice answer sheet that sound the most logical would be x+2=-1/8y^2 and x-2=...

**Trigonometry**

cos2x(2cosx+1)=0 x=?

**calculus I**

thanks!!

**calculus I**

Find the tangent line approximation to 1/x when x=1 How do i find tangent line approximations??? my prof hasn't gone over this and i don't understand how to do it.

**Caculus I**

If f is decreasing and f(20)=10, which of the following must be incorrect? Explain. a. (f^-1)'(20)=-3 b. (f^-1)'(10)=12 how do i work this problem? i'm kind of confused about inverse functions.

**history**

what items would you carry on a trip in the 15th century?

**calculus**

Given f(x)=2x^3-7 find f^-1(x) and then find f^-1(-2) I though that this meant inverse function. x=2y^3-7 x+7=2y^3 (x+7)/2=y^3 ((x+7)/2)^(1/3)=y so this meant f^-1(-2) = 1.35721 The professor posted the answer as being 6. I'm not sure if I misunderstood the question or if ...

**Math**

For a period of time as an alligator grows, its mass is proportional to the cube of its length. When the alligator's length changes by 15.8%, its mass increases by 17.3kg. Find its mass at the end of this process.

**Science**

An object accelerates (changes its speed) only if the forces acting on it in one direction are greater than the forces in the opposite direction, All of the following objects will accelerate EXCEPT? A) a ball striking a wall, in which the force of the ball on the wall is equal...

**Science**

Ions are electrically charged particles that are formed when certain compounds are dissolved in water. These solutions will conduct electricity. The Swedish scientist Svante Arrhenius coined the term ion (which means wanderer) to explain why solutions of electrolytes will ...

**HELP! ASAP! SPANISH!**

i am writing a poem for spanish and in the poem we have to say a phrase about an animal. i have a crocodile. what is a good phrase that i can say in spanish about a croc? thanks sooo much!

**history**

in 1920 the republicans did something they hadn't done in a very long time. What was it?

**Physics**

List at least two major potential asvantages of power production by fusion rather than by fission.

**Physics**

Explain how redioactive decay has always warmed the Earth from the inside and how nuclear fusion has always warmed the Earth from the outside.

**Physics**

If a pair of carbon atoms were fused, and the product were to emit a beta particle, what element would be produced?

**Physics**

Mixing copper and zinc atoms produces the alloy brass. What would be produced with the fusion of copper and zinc nuclei?

**Physics**

Which process would release energy from gold, fission or fusion? Which would release energy from carbon? From iron?

**RECETAS**

jugo de naranja? vas al supermarche

**chemistry**

How many grams of NaOH are present in 5.0 mL of a 1.0% (m/v) NaOH solution?

**chemistry**

thank you! Irvine is bomb Chem 1C is a bummer lol

**Physics**

Who was the scientist that invented the uncertainty principle ? Was it Heisenberg?

**Physics**

An electron and a proton are traveling at the same speed. Which one has the longer wavelength?

**Physics**

In the photoelectric effect, what determines the number of ejected electrons?

**Physics**

In the photoelectric effect, what determines the kinetic energy of the ejected electrons?

**Physics**

Which laser beam carries more energy per photon? red, yellow, green, violet? I think red. Am I right?

**languages**

are there any free downloadable courses that I could teach myself Arabic with? I can't seem to find any good ones.

**math-patterns**

Each number adds a digit: Example 6,38,932,1087,12437,123456,1234567,12345678,123456789, ect... The pattern is not the number itself, but how many numbers in each... Good Luck!

**Chem**

1)Br- + MnO2 + 3H2O Mn2+ + BrO3- + 2H3O+ 2)Br- + 3MnO2 + 6H3O+ 3Mn2+ + 9H2O + BrO3- 3)6Br- + MnO2 + 48H2O Mn2+ + 32H3O+ + 6BrO3- 4)4Br- + 3MnO2 + 18H2O 3Mn2+ + 12H3O+ + 4BrO3- 5)Br- + 3MnO2 + 3H3O+ 3Mn2+ + BrO3- + 3H2O I got the first one. Is that right?

**Chem**

Manganese dioxide reacts with bromide ions to form manganese ions and bromate ions in an acidic aqueous solution. Write the balanced equation for this reaction. 1)Br- + MnO2 + 3H2O --> Mn2+ + BrO3- + 2H3O+ 2)Br- + 3MnO2 + 6H3O+ ---> 3Mn2+ + 9H2O + BrO3- 3)6Br- + MnO2 + ...

**Chem**

Calculate the Go for the oxidation of 5 moles of tin in the following balanced reaction. 16HCl + 2KMnO4 + 5Sn ---> 5SnCl2 + 2MnCl2 + 2KCl + 8H2O

**Is this how you derive the formula for arc length?**

For a smal change in x, dx: ds² = dx² + dy² ds = sqrt [(dx² + dy²)] s = INTEGRAL of sqrt [(dx² + dy²)] s = INTEGRAL of sqrt [(dx² + dy² * dx²/dx²)] s = INTEGRAL of sqrt[(1 + dy² * 1/dx²)] dx s = INTEGRAL of sqrt...

**accounting**

what is the most important step in the acounting cycle

**Calc-Derivatives**

I asked this before and did not get a response so I am trying again. (Note, I didn't know how to type the symbol for pi) What is the derivative of: 2pi^2r^4 would it simply be 8pi^2r^3? I was thinking the 2pi^2 is simply the equivalent of a constant in front of the r^4 and...

**calc**

What is the derivative of: 2pi^2r^4 would it simply be 8pi^2r^3? I was thinking the 2pi^2 is simply the equivalent of a constant in front of the r^4 and so you would just use the power rule.

**Calc**

Can this be factored: 6/5x^1/5 - 12/5x^-4/5 I am trying to find the values for X which will make this equal to zero. My factoring looks like this but not sure it is right 6/5x^1/5(1-2x^-1) so I get X= 0 and X=2

**social studies**

who does John Hancock resemble, and how?

**Physics**

Can two equipotentials ever cross one another? Explain via analogy to a topographical map Can two equipotentials be tangent to one another? What is the analogous situation in the case of a topographical map? What is your thinking on this? I will be happy to critique your ...

**Physics**

For a resonance tube apparatus (open ended on one side) with a total tube length of 1.00 meter, on a day when the speed of sound is 340 m/s, how many resonance positions will be observed as the piston position is varied for a frequency of 500 Hz? and 1000 Hz? Use the n as the ...

**Physics**

Why should a tuning fork be set into oscillation by striking it with a soft rubber mallet rather than with a hard metal mallet? Striking it with a hard mallet excites higher order modes rather than mainly the fundamental. That is because a hard mallet impact causes steep ...

**Physics**

Does centripetal force acting on an object in uniform circular motion do work on the object? For work, force must be in the direction of movement. Please stop posting under differing names.

**chem expirement!**

You are required to design an experiment to test Hess's law using the combustion of ethanol. Write a brief design for this experiment. What I wrote as my answer: Hess’ Law: is the algebraic addition of chemical equations yields a net equation whose enthalpy of ...

**chem experiment:**

You are required to design an experiment to test Hess's law using the combustion of ethanol. Write a brief design for this experiment. What I wrote as my answer: Hess’ Law: is the algebraic addition of chemical equations yields a net equation whose enthalpy of ...

**Calc Help**

I need to find dq2/dpb and dqb/dpa qa=2500+(600/pb+2)-40pa qb=3000-100pb+(400/pa+5) a and b are subscripts.

**Calc Help**

Marginal Cost = 30sqroot(x+4) with fixed costs of $1000. Marginal Revenue = 900. find profit or loss from production and sale of 5 units. how many units will result in a max profit? what is the max profit? Can someone please help. Trying to review for my final and really stuck...

**Calc Help**

demand = (p+1)sqroot(q+1)=1000. Find elasticity of demand at a price of $39 per unit. I am really struggling with this problem is there anyone that can help me? i am not familiar with the terminology, but if you are trying to solve for p, it is not that hard (p+1)√(p+1...

**algebra**

A bicyclist rode into the country for 5hr. In returning her speed was 5 mi/h faster and the trip took 4 hr. what was her speed each way? What equation would I use to solve this problem i have no idea Let V be her speed going out, so V+5 will be her speed coming back. Let the ...

**calculus**

i'm having trouble with a problem in my calc class...it isn't really calculus yet since we're still in the review section but it goes somethign like this: ( don't have it in front of me) a rational function is defined by: R/(x-K) where R and K are constants. ...

**Calc Help**

Find two functions that this could be the derivative of: y'=4x+7 Remember the derivative of any constant is zero. take its antiderivative i suppose... y= 2x^2 + 7x + any number

**Calc Help**

An agency charges $15 per person for a trip for groups of no less than 30 people. But for each person above the 30, the charge (for everyone!) will be reduced by $0.15. Write a revenue function for the agency usin x as number of people above 30. What size group will maximize ...

**Calc Help**

The daily sales, S, in thousands of dollars, is a function of the money, x, spent on advertising (in thousands of dollars) according to: S(x)= -x^3+9x^2+6/6. Find the x-coordinate of the point of diminishing returns. How much money is spent on advertising when you reach the ...

**Calc Help**

f(x)=x^4-16x^2. Is this function concave up or down at x=-2? I will be happy to critique your thinking.

**Calc Help**

Find the 4th derivative of y=4x^3-(2/x). Reads: 4x to the third minus 2 divided by x. I will be happy to critique your thinking. We don't do homework or tests.

**Calc Help**

Differentitate y= x^2(sqroot4x-3). Do not simplify. Reads: x squared times the square root of (4x minus 3)

**Organic Chemistry**

What is the product formed from a reaction of butanal and sodium hydroxide? cyclopentanone and sodium hydroxide? acetophenone and sodium hydroxide? Thanks. You want to look up information about the Aldol condensation.

**organic chemistry**

which alcohol and carboxylic acid would produce benzyl isobutyrate by Fischer esterification? and which alcohol and carboxylic acid would produce isobutyl benzoate by fischer esterification? I can't find anything about Fischer esterification specifically. But acids + ...

**fischer esterification**

which alcohol and carboxylic acid would produce benzyl isobutyrate by Fischer esterification? and which alcohol and carboxylic acid would produce isobutyl benzoate by fischer esterification? Since this is not my area of expertise, I searched Google under the key words "...

**Chemistry Help!!!**

How will the osmotic preassure of an aqueous solution change as evaporation occurs? A.The osmotic preassure will increase. B.The osmotic preassure will not change. C.The osmotic preassure will decrease. D.The osmotic preassure will increase or decrease until it equals the ...

**Phenol/Nitirc Acid Reaction**

Is it possible to illustrate the reaction mechanism for phenol with nitric acid? no well thank you, you have been most helpful

**chemistry-lab**

2.What does it mean to “follow the course of a reaction”? I would imagine it means to find the overall order of the reaction and make it in to a rate law equation. That's part of it. It can mean, in addition, to knowing any intermediates formed and how they react...

**MATH/LOGIC**

You have gotten reservations from Fly By Night Tours to an island off the coast of Florida. You arrive and find out that the island is occupied and administered by alligators and crocodiles. You are confronted by a committe of three of these reptiles with the following ...

**chemistry**

Consider the equilibrium, A + B <--> C, with K=32.217 and initial concentrations of A,B, and C, of 3.665M, 0.883M, and 3.925M, respectively. What is the equilibrium concentration of B 3.665 0.883 3.925 A + B = C Keq=(C)/(A)*(B)= 32.217 Q = (3.025)/(3.665)*(0.883)=1.21 Q...

**chemistry**

If, for a second-order reaction, the elapsed time after the first half-life is 338.871 seconds, the elapsed time after four half-lives would be (in minutes)... t1/2= 1/k(A). k= 1/t1/2*(A)=1/338.871 s(1) (I let (A)=1). k = ?? After 4 half lives, beginning of the 5th, (A) = 1/24...

**chemistry**

The temperature at which a reaction is running is increase from 11.052 celsius to 102.567 celsius. If the rate constant increases by a factor of 5.608, what is the activation energy of the reaction in kJ/mol? Use the Arrhenius equation. I AM STILL LOST The Arrhenius equation ...

**algebra**

It is at that height going up and coming down in its path throughout its motion. The path is illustrated like an upside down u. The times are after leaving what propelled it upward and as it falls back to earth via gravity.

**spelling**

whirlwind is to breeze as downpour is to ?

**trigonometry**

Expanding the trinomial, (x+y+z)^n, gives terms X^rY^sZ^t where r+s+t=n and with a coeficient of n! over r!s!t!. a. use this pattern to expand (x+y+z)^3. b. find the sum of the coeficients in the expression of (x+y+z)^n. (LET x=y=z=1.)

**trigonometry**

suppose a manufacterer of transistors believes that, on the average, one defective transistor occurs in every 100 transistors. a. find the probability that a batch of 20 transistors has 2 defectives. b. find the probability that a batch of 20 transistors has at most 2 ...

**english/poetrey?**

why do poets use diction? Thank you for using the Jiskha Homework Help Forum. For an excellent definition of "diction" try this site: http://bcs.bedfordstmartins.com/Virtualit/poetry/diction_def.html

**#6, week 15**

what peninsula do the Wolverines go past to get to Green Bay? Thank you for using the Jiskha Homework Help Forum. The Wolverines are from Michigan and the Green Bay Packers from Wisconsin. Get a good map and look between Michigan and Wisconsin. A peninsula is surrounded on 3 ...

**Physics QUIZ**

Rising air cools as a result of a decrease in barometric pressure with altitude. (Lapse Rate) True/False? When an inflatable life jacket is inflated with a compressed air cylinder the air inside the now inflated life jacket is much colder than it was prior to inflation when it...

**Calc Jacobian**

Thanks "I know that the xy region is the line x=y y=0 and y=1- x/2)" It is helpful to rewrite the region in the x-y plane by specifying the three lines and the endpoints, i.e. the points where they intersect. If you insert these points in the formula for U and V you ...

**HAMLET!!!**

How are the ghost’s entrances made impressive? Look at the lines of whoever's speaking just before the ghost appears each time. What is the topic of discussion? Are there any consistencies in this for the two times the ghost appears? ??

**Health & Safety**

I am an instructor at a small college in the UK. The college has recently purchased a multi media (POWERPONT) projector & lap top. I am keen to utilise this new medium in my lectures but in my opinion the college have not provided appropriate facilities to enable this. Other ...

**bio**

If our tongue is only sensitive to sweet, sour, salt, and bitter tastes, how are we able to detect so many different flavors? http://faculty.washington.edu/chudler/tasty.html

**Trigonometry**

What is cos (pi/2 - x) secx using the fundamental identities to simplify the expression. I think I have the right answer but I want to check to make sure. Well, cos (pi/2 - x) is something you should've seen already. It's just another name for sin(x). Also, sec(x) is ...

**Ethics**

We are studying Japanese in my Ethics class. It says in the reading they have many fatiths. Does anyone know why that is? What is fatiths? You might mean faiths, if so try: (Broken Link Removed) AND http://www.google.com/search?as_q=&num=10&hl=en&btnG=Google+Search&as_epq=...

**math**

please help me simplify this exponent 24^-1a^-3/6^-2b^-2 Basically it's this right?: (24^-1 * a^-3) / (6^-2 * b^-2) so: (1/24 * 1/(a^3)) / (1/(6^2) * 1/(b^2)) you should know that 6^2 = 36 so 1/(6^2) = 1/36 Now multiply: (1/(24a^3)) / (1/(36b^2)) Then flip: (24a^3) / (36b^...

**math**

5x^-1/-y^-1 once again, what are you asking? how is this simplified -y/5x Whenever you have anything raised to the negative power, flip it upside down. So: X^-1 = 1/X or X^-3 = 1/(X^3) Whenever anything is raised to the 1 power, it is itself. X^1 = X 12398719283719^1 = ...

**math**

2k^-1/18m^-3 2k^-1/18m^-3 = 18m^3/2k

**Science**

A supersonic jet flying at 145 m/s is accelerated uniformly at the rate of 23.1 m/s squared for 20.0 s. a. What is its final velocity? b. The speed of sound in air is 331 m/s. How many times the speed of sound is the plane's final speed? I don't care what it is. ...

**math**

Determine whether there are 2 consecutive odd integers such that 5 times the first exceeds three times the second by 54. Can anyone help??? We're asked: Determine whether there are 2 consecutive odd integers such that 5 times the first exceeds three times the second by 54...

**Math**

What is the exact value of sin 5ð and how do you find it? type in the google search engine.. sin(5degrees) It will compute it for you. It appears you pasted something that the ASCII didn't translate. You'll need to type out the value for the angle.

**Stoichiometry problem**

@Malogis I agree 100% :P

**history**

The ingredient that someone gave to me for my Fijian banana scones is not clear because I don’t know how much milk I am suppose to pour in the recipe. Scone? Add enough milk to make a thick batter, as if you were making cornbread. Ask your mom what "thick batter"...

**history**

Hi, I have to make a Fijian recipe for my history class; I have chose to do Fijian banana scones, but unfortunately the recipe that I have found is not very good. I would greatly appreciate if someone helps me find clearer ingredients so I can make it. Thank you How about this...

**history**

Can someone please help me find information o Fiji. These are the topic I will be focusing on!