Friday

October 31, 2014

October 31, 2014

Total # Posts: 2,820

**Chemistry**

Beryllium flouride's formula is BeF2. Why do beryllium and flourine combine in a 1:2 ratio?
*October 30, 2014*

**Math**

Limit as n goes to infinity of ((2n)!/(n^n)).
*October 29, 2014*

**math**

Anthony is 20. and julian is 10.
*October 29, 2014*

**Calculus**

Find the work done by F(x,y,z)=(x^2y)i=(x-z)j+(xyz)k where c=(t)i+(t^2)j+(2)k, 0<t<1. The answer is supposed to be -17/15, but i keep getting -13/10. Any help on the process would be appreciated.
*October 28, 2014*

**Math**

The medical records of infants delivered at Kaiser Memorial Hospital show that the infants' lengths at birth (in inches) are normally distributed with a mean of 22 and a standard deviation of 2.1. Find the probability that an infant selected at random from among those ...
*October 27, 2014*

**Physical Science**

I am so confused. I do not get it at all.
*October 27, 2014*

**Physical Science**

A 5.00 kg block of ice at –25 oC is converted to steam at 125 oC. How much energy (in kilojoules) is expended in this process? The following data are provided: a. Specific heat of ice = 2.092 J/g oC b. Latent heat of fusion = 334.72 J/g c. Specific heat of water = 4.184 J...
*October 27, 2014*

**Physical Science**

Lead is a soft, dense metal with a specific heat of 0.117 J/goC, a melting point of 328.0 oC, and a heat of fusion of 23012 J/g. How much heat (in kilojoules) must be provided to melt a 350.0 kg sample of lead that is initially at 20 oC?
*October 27, 2014*

**Limits**

I know that 1/n goes to zero so 2^0=1 so obviously the limit is 1. But i have to write it out and I can't seem to figure out the correct way to do this.
*October 27, 2014*

**Limits**

Prove using formal definition of limit: Lim 2^(1/n)=1 n->ininity
*October 27, 2014*

**Mathematica**

I am trying to write a matrix where n=100, and the matrix's first and last number is 2 and all the number in the middle are 1.
*October 26, 2014*

**Clark Atlanta**

Plants need carbon dioxide to produce energy. How many carbon are there in 10.0 g of carbon dioxide? this is what I have so far. 10.0g x 1mol/44.01CO2 = 227 mol CO2
*October 26, 2014*

**8th grade language arts**

Can someone post the answers to this question please.
*October 25, 2014*

**phyics**

_________ was the first to show that all objects fall toward Earth with constant ____________.
*October 23, 2014*

**Proof**

Let {x_n} and {y_n} be real valued sequences suppose x_n->0 and {y_n} is bounded. Prove that (x_n*y_n)->0
*October 22, 2014*

**Calculus**

Use linear approximation, i.e. the tangent line, to approximate \sqrt[3] { 7.9 } as follows: The equation of the tangent line to f(x) at x = 8 can be written in the form y = Using this, we find our approximation for \sqrt[3] {7.9} is
*October 21, 2014*

**Chemistry**

How would the empirical formula of copper (II) sulfate be affected if some of the sample sticks to the stirring rod?
*October 20, 2014*

**Math**

If the first dice yields an even number, what is the probability that the sum of the two dices will be equal to 12? 1st Die P(even) = 3/6 = 0.50 P(6|even) = 1/3 = 0.333 2nd Die P(6) = 1/6 = .1667 So P(12) = 0.33*0.1667 ?
*October 19, 2014*

**Probability**

If the first dice yields an even number, what is the probability that the sum of the two dices will be equal to 12? 1st Die P(even) = 3/6 = 0.50 P(6|even) = 1/3 = 0.333 2nd Die P(6) = 1/6 = .1667 So P(12) = 0.5*0.33*0.1667 ?
*October 19, 2014*

**algebra**

what is the area of a rectangle with a length that is 5 more than triple the width?
*October 16, 2014*

**calculus**

Find the center of mass in the 1st quadrant of the circle x^2+y^2=4 where rho(x,y)=k(x^2+y^2) Thanks.
*October 15, 2014*

**math**

Marcus Has 5 sticks, He gave away 0.75 of each stick away. How Many Did He He Give Away
*October 15, 2014*

**English Writing**

Can you help me write a persuasive paragraph? The topic is about 'Disposal Food'
*October 15, 2014*

**spanish**

en el primer piso puedes encontrar
*October 14, 2014*

**Poofs**

Let {X_n} be a sequence of real numbers that is bounded above by M and such that X_n-->x Prove that x<=M. This is what I have, but I believe it is wrong: Let M>0 then there exist N>=1 s.t. n>=N. then |x_n - x|<M. Since {x_n} is bounded above by the given {x_n...
*October 13, 2014*

**Math Proof**

Let {X_n} be a sequence of real numbers that is bounded above by M and such that X_n-->x Prove that x<=M
*October 13, 2014*

**Physics**

I'm having a bit of trouble with this problem. A ball is thrown upwards and stays in the air for 3.65 seconds. What is the initial velocity? (I use an acceleration of -10 m/s/s) I got an answer of 18.25 m/s/s but I'm not sure that it's correct. I would love some help!
*October 10, 2014*

**Physics**

I'm having a bit of trouble with this problem. A ball is thrown upwards and stays in the air for 3.65 seconds. What is the initial velocity? (I use an acceleration of -10 m/s/s) I got an answer of 18.25 m/s/s but I'm not sure that it's correct. I would love some help!
*October 9, 2014*

**Physics**

Thanks so much!
*October 9, 2014*

**Physics**

I'm having some trouble figuring out how to do the following question: A ball punted vertically has a hang time of 3.65 seconds. What was its initial velocity? (I use an acceleration of -10 m/s/s) Thanks!
*October 9, 2014*

**Math**

You can use the Pythagorean equation (a^2 + b^2= c^2 ) because the triangle the diagonal and the 2 sides make is a right triangle. H= height of rectangle 14+H= width of rectangle H^2 + (14+H)^2 = 26^2 Solve for h to find height:)
*October 9, 2014*

**math**

Yolo has two pieces of string. One is 32 inches long, and the other is 48 inches long. She wants to make as many necklaces as she can, all of the same length. What is the longest a necklace can be?
*October 8, 2014*

**Math**

There are 54 graders who play sports. Twenty-seven play baseball. The rest play soccer. Second grade has 37 soccer players. How many students play soccer?
*October 8, 2014*

**Statistics**

You own shares of Fidelity Magellan Fund (FMF), which concentrates on stocks of large American companies. Its monthly return is μFMF = 1.4% and sFMF = 4.70%. You decided to diversify your portfolio by adding shares of the Fidelity Japan Fund (FJF), which has monthly ...
*October 8, 2014*

**Statistics**

In a sophisticated medicine research center, two scales are used for repeated weighing of the same item. If the true weight of a compound is 2 grams [g], the first scale produces readings X that have a mean 2.0 g and standard deviation 0.03 g. The second scale’s readings ...
*October 8, 2014*

**Math**

An airplane flys at a constant altitude of 2 miles and a constant speed of 600 miles per hour on a straight course that will take it directly over a kangaroo on the ground. How fast is the angle of elevation of the kangaroo's line of sight increasing when the distance from...
*October 7, 2014*

**English**

After one drink, he drank another, it means that he fluidly drank a lot, until he fell asleep
*October 6, 2014*

**Pre Calculus**

It does not say anything really about finding how many positive and negative roots. It only says how you can find the number of zeros.
*October 6, 2014*

**Pre Calculus**

Using Descartes' Rule of Signs how can you determine the number of positive and negative zeros (roots) a polynomial may have?
*October 6, 2014*

**History *repost* (sorry!)**

Yes, I believe so
*October 6, 2014*

**Math**

I see, for this problem you would have to plug in numbers with trial and error, by doing this you get x=-2 as one of the roots, then you would factor (x+2)out of the problem. Then you would get x²-6x+9. This is a perfect square, so when you factor that, you get (x-3)^2. ...
*October 6, 2014*

**Math**

You would factor by grouping
*October 6, 2014*

**AP English Language and Comp**

Chillingworth, because he practically devoted his whole life to evil
*October 6, 2014*

**AP English Language and Comp**

Whose sin is blacker- Chillingworth's or Dimmesdale's? Why? (The Scarlet Letter)
*October 6, 2014*

**Algebra II**

You are correct!
*October 6, 2014*

**Geography**

By footprints do you mean carbon footprint? If so, countries with larger carbon footprints are generally more advanced and are industrialized, while countries with smaller footprints are generally less developed.
*October 6, 2014*

**Pre Calculus**

It says, Use the Factor theorem to determine whether x-c is a factor of x: f(x)=-4x^3 +5x^2 +8 and c=-2 That is what it says in the textbook
*October 6, 2014*

**Pre Calculus **

If f(x)=-4x^3 +5x^2 +8 and c=-2 is c a factor of x?(Use the Factor Theorem)
*October 6, 2014*

**Math**

They are imaginary because a negative number cannot be square rooted.
*October 6, 2014*

**Math Proof**

0<=b_n<=a_n. a) if a_n-->0 then b_n-->0. b) if a_n-->infinity then b_n-->infinity I don't know where to start.
*October 6, 2014*

**math**

Is she giving 3 pieces of candy to each student?
*October 6, 2014*

**Algebra**

Find a number such that the sum of two times the number and six times its reciprocal is 79/5.
*October 6, 2014*

**US History**

The teacher didn't give us a textbook, I would just like to know the different economic purposes between the two colonies.
*October 5, 2014*

**US History**

Can you elaborate on that a little bit more?
*October 5, 2014*

**US History**

Although the New England, and the Chesapeake region were both settled largely by people of english orgin, by 1700 the regions had evolved into 2 distinct societies. Why did this difference in development occur?
*October 5, 2014*

**Geography**

Should geographers regard culture and social customs as generalizations about a group of people, or should they say it comes from people's interaction with the physical environment?
*October 5, 2014*

**math**

In mathematics class, 30 students received an A on the third test, which is 125% of the students who received an A on the second test. How many students received an A on the second test?
*October 5, 2014*

**math**

explain what do you need to do to extend number pattern?
*October 2, 2014*

**Pre-Calculus/Trigonometry**

-y=-3x y=3x 5x+2(3x)=22 5x+6x=22 11x=22 x=2 y=3(2) y=6
*September 29, 2014*

**EVERYONE**

HI. For one of my classes i need to invent/innovate a product. So it is a year long project and if anyone has anyone sort of ideas it would be really helpful. Thanks (Thin along the lines of what you really hate and need fixed)
*September 29, 2014*

**Numerical Analysis**

Find the parabolically terminated cubic spline through the data ppoints (0,1),(1,1)(2,1)(3,1),(4,1). Is this spline also not-a-Knot? natural?
*September 29, 2014*

**math mks**

the tempreture was -8 f at 6 a.m. and rose 15 f at 9 a.m. the answer is 7 what is the question?
*September 29, 2014*

**Physics**

A swimmer, capable of swimming at a speed of 1.44 m/s in still water (i.e., the swimmer can swim with a speed of 1.44 m/s relative to the water), starts to swim directly across a 2.21-km-wide river. However, the current is 0.840 m/s, and it carries the swimmer downstream. (a) ...
*September 28, 2014*

**physics**

A radar antenna is tracking a satellite orbiting the earth. At a certain time, the radar screen shows the satellite to be 118 km away. The radar antenna is pointing upward at an angle of 58.2 ° above the ground. Find (a) the x and (b) the y components (in km) of the ...
*September 28, 2014*

**Abstract Algebra**

If G is a group with exactly 66 elements of order 14, how many subgroups of order 14 does G have?
*September 26, 2014*

**math problem (please help)**

d. (f+g)(x)=f(x)+g(x), just add the two polynomials together. you'll get 5x^2-x-4
*September 26, 2014*

**math problem (please help)**

switch your x and y like original : y=(7x-8)/(x-1) to: x=(7y-8)/(y-1) and solve for y. so: xy-1=7y-8=> xy-7y=-7=> y(x-7)=-7 => y=-7/(x-7)
*September 26, 2014*

**statistics**

The 92 million Americans of age 50 and over control 50% of all discretionary income (AARP Bulletin, March 2008). AARP estimated that the average annual expenditure on restaurants and carry out food was $1873 for individuals in this age group. Suppose this estimate is based on ...
*September 26, 2014*

**Chemistry**

A scientist wants to make a solution of tribasic sodium phosphate, Na3PO4, for a laboratory experiment. How many grams of Na3PO4 will be needed to produce 400mL of a solution that has a concentration of Na+ ions of 1.10M ?
*September 24, 2014*

**Metric Spaces Proof**

d(x,y)={ 1 if x does not equal y 0 if x=y Prove that d satisfies the axioms of a metric. clearly it satisfies d(x,y) existing in the reals, and d(x,y)>=0 and d(x,y)=0 iff x=y. why I don't know is triangle inequality and d(x,y)=d(y,x).
*September 24, 2014*

**Math Proof**

On the real line, define d (x, y ) = sqrt(abs(x − y)) . Prove that d satisfies the axioms of a metric.
*September 24, 2014*

**math**

I wasnt given any
*September 24, 2014*

**math**

What is the domain and range of ln(4-x-y)
*September 24, 2014*

**math**

I am number less than 10. When I am divided by 2, half of that number is also 2. what number am I?
*September 21, 2014*

**Physics**

A relativistic proton has a momentum of 1.0×10^-17 kg ∙ m/s and a rest energy of 0.15 nJ. What is the kinetic energy of this proton? (c = 3.00 × 108 m/s, mass of proton = 1.67 × 10-27 kg)
*September 21, 2014*

**physics**

A car travels along a straight stretch of road. It proceeds for 11.4 mi at 57 mi/h, then 21.8 mi at 43 mi/h, and finally 30.8 mi at 32.6 mi/h. What is the car’s average velocity during the entire trip?
*September 20, 2014*

**math**

I am a whole number. when you add 3 to me you get a 2-digit number. The 2-digit number is the same as 3 four times. What number am I?
*September 18, 2014*

**Physics**

1. A cannon mounted on the back of a ship fires a 50.0 kg cannonball in the horizontal direction at a speed of 150 m/s. If the cannon and ship to which it is firmly attached have a mass of 4.00 x 103 kg and are initially at rest, what is the speed of the ship just after ...
*September 18, 2014*

**math**

Write an equation relating the number of questions I get right on a test to the total score I will get if the test has 20 questions each with the same point value and the test is worth 100 points total. I know each question is worth 5 points so I would think that N (number ...
*September 17, 2014*

**MATH**

4X/5+1/7=8
*September 16, 2014*

**Math Proof:**

Can you say: Since x in E then E is not empty and is a subset of the reals. Since there exist and x in E where a<x then a is a lower bound of E. then let lambda be a different lower bound in E then let a precede lambda. this can't occur because we stated that a is a ...
*September 16, 2014*

**Math Proof:**

Let a,b exist in the reals with a<b. (i) for the open interval E=(a,b), prove that infE=a and supE=b. (ii) for the closed interval F=[a,b], prove that the infF=a and infF=b.
*September 16, 2014*

**Math Proof**

Prove: Let a,b exist in the reals with a<b, (i) For the open interval E=(a,b) prove that the inf E=a and sup E=b (ii) for the closed interval F=[a,b], prove that inf F=a and sup F=b.
*September 15, 2014*

**Math Proof**

Find a rational number and an irrational number between x=8.9949926 and y=8.995
*September 13, 2014*

**chemistry**

The typical person needs a 2000 calorie diet to sustain “normal” activity. Nowadays, a lot of the energy in American diet comes from fats and sugars. Assume that “fats” provide 9.0 calories per gram and sugars (treat as glucose) provide 4.5 calories per ...
*September 13, 2014*

**Numerical Analysis**

Consider the equation 8x^4 − 12x^3 + 6x^2 − x = 0. For each of the two solutions x = 0 and x = 1/2, decide whether the Bisection Method or Newton’s method will converge faster (say to eight place accuracy), without running the calculation. I don't ...
*September 12, 2014*

**Math Proof**

Let S be a non-empty subset of the real numbers that is bounded below. Define −S by −S = {− x | x ∈S }. Prove: (i) −S is bounded above. (ii) sup(−S) = − inf S .
*September 10, 2014*

**Math**

What's the question asking you to do? Because if it just the two sides equal then you are missing a 2
*September 10, 2014*

**Calculus**

Determine the exact values of the six trigonometric functions of the angle.(-5,-2)
*September 8, 2014*

**Math Proof**

Prove: let alpha be a lower bound of a subset E of an ordered set S. If alpha exist in E, then alpha= infE(greatest lower bound of E). PF: Already have alpha is a lower bound of E. Let lambda be a different lower bound of E. If alpha precedes lambda, the lambda will not be a ...
*September 8, 2014*

**Math Proof**

Thank you! Could you also factor sqrt(12) to be 2sqrt(3) and prove sqrt(3) to be irrational by assuming rational?
*September 8, 2014*

**Math Proof**

Prove that square root of 12 is irrational. **I don't know if I did this correctly PF: By contrapositive, assume sqrt(12) is rational. Then there exist an a,b as integers such that a/b is written in the lowest terms, and sqrt(12)=a/b. Then by squaring both sides, 12=a^2/b^...
*September 8, 2014*

**Math Proof**

Thank you!
*September 8, 2014*

**Math Proof**

If c is rational, c does not = 0, and x is irrational, then cx and c+x are irrational.
*September 8, 2014*

**child care**

Which one of the following statements about childcare centers is correct? A. Childcare centers are automatically enrolled in a QRIS system when they apply to be licensed. B. Childcare centers are mandated by law to enroll in a QRIS system. C. Childcare centers voluntarily ...
*September 7, 2014*

**child care**

Any business, including a child care facility, must obtain an Employer Identification Number (EIN) to establish its business tax accounts. The EIN is assigned by the A. Internal Revenue Service (IRS). B. local Chamber of Commerce. C. State Department of Education. D. National ...
*September 7, 2014*

**Numerical Analysis**

use a graph, or guess and then confirm a bracket, or tabulate f(x) on a wide interval to figure the bracket of length one. to find an interval of length 1 that contains a root of the equation 3x^3 +x^2=x+5. I don't understand what to do
*September 2, 2014*

**college algebra**

question 1: build the fraction x+5/x+3 to an equivalent fraction whoes denominator is x^2 question 2: simplify (x^2+6x+9)(3-x)/(x-3)(2x+6) question 3. find the product in simplest from x^3-9x/x^5+27x^2 * x^2-3x+9/x^2+3x
*September 2, 2014*

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