# Posts by sarah

Total # Posts: 5,778

**CALCULUS**

Let y(t) denote the mass of a radioactive substance at time t.t. Suppose this substance obeys the equation y′(t)=−14y(t). Assume that, initially, the mass of the substance is y(0)=M>0. At what time does half of the mass remain? (Round your answer to 3 decimal ...

**CALC PLEASE HELP**

Suppose that y′=ky, y(0)=7, and y′(0)=4. What is y as a function of t ? PLEASE EXPLAIN

**CALCULUS**

∫4x^−1*sin(ln(6x))dx I got 4*[-cos(ln(6x))]+C but its wrong and im not sure why... Please Help!! Thanks

**CALC**

Find the area of the region bounded by: y=2x−tan0.18x, x=1, x=5, y=0 Round your answer to 3 decimal places. I get 9 but its wrong! please help

**Calculus**

to make it continuous f(2)=a so it would equal -1?

**Calculus**

So a=-1 That makes sense because it's continuous

**Calculus**

find the value of a, if it exists, such that the following function is continuous at X = 2. piecewise function f(x)={x^2-3x+1, if x>2; a, if x=2; 3-2x, if x<2 I found the limits from left and right of 2 = -1 so the limit exists but I don't know how to figure out a

**Math**

Among a group of people, 10% are from NYC and 90% are not. All people from NYC are under 18 years old, and 70% of those not from NYC are also under 18 years old. One person is chosen at random, and he or she is under 18. What is the probability that the person chosen is from ...

**CALCULUS**

Find the derivative of y=4sinx−2cosx

**Business Math**

How long will it take for an investment to double at 7% p.a compounded monthly?

**Calc**

Find the derivative of y=4sinx−2cosx

**Calculus**

let f(x)=2x-7. Use the rigorous definition of limit to show that lim x-->4 f(x)=1

**English**

Can you summarize this case study 300 words minimum? Overview Hospital A: Porter Regional Medical Center (PRMC) Located on the east side of town, Porter Regional Medical Center (PRMC) was a for-profit hospital, consisting of 110 hospital beds, 8 of which were reserved for ...

**geography**

Under the Soviet system, the government a. controlled all forms of communication. b. allowed newspapers to print whatever they wanted. c. controlled editorials but not the reporting of news. d. encouraged access to a wide variety of news sources.

**math**

Find each value if cos A=12/13 with 0 (degrees) <= A <= 90 (degrees) and if sin B=8/17 with 90 (degrees) <= B <=180 (degrees) 1. sin(A+B) 2. cos(A-B) 3. tan(A-B)

**Teachers aide**

What are two types of wheelchairs used by the physically challenged students are the ?I think the two would be a orthosis and the power driven

**Geometry**

31.Identify the Hypothesis of the statement below. If you are riding on a train, then it will stop at every station on the line. A.You are riding on a train B.It will stop at every station on the line C.You are not riding on a train D.It will not stop at every station on the ...

**Math**

15 blocks

**math plz help my last chance to do this homework**

how do you post a pic

**math plz help my last chance to do this homework**

a) write an expression in simplest form for the perimeter of each triangle. b)write another expression in simplest form that shows the difference between the perimeter of the larger triangle and the perimeter of the smaller triangle.

**Algebra**

i think a is right

**Algebra**

Randall wants to mix 41 lb of nuts worth $2 per lb with some nuts worth $8 per lb to make a mixture worth $7 per lb. How many pounds of $8 nuts must he use? Pounds of nuts-cost per pound-total cost 41-$2-? x-$8-? ?-$7-? There is a chart and I...

**Algebra**

A chemist wishes to mix a solution that is 4% acid. She has on hand 66 liters of a 2% acid solution and wishes to add some 8% acid solution to obtain the desired 4% acid solution. How much 8% acid solution should she add? There is a ...

**Algebra**

The height of Tower A is 940 feet more than Tower B. The two towers have a combined height of 1,540 feet. What are the heights of each tower?

**BOB PURSLEY PLEASE HELP**

What is the electrostatic force between one object with a charge of +5.0 × 10−6 C, and a second object with a charge of +2.0 × 10−6 C? The objects are 1.2 meters apart. In a pith ball experiment, the two pith balls are at rest. The magnitude of the ...

**URGENT HELP**

1.In a pith ball experiment, the two pith balls are at rest. The magnitude of the tension in each string is |T| = 0.55 N, and the angle between each string and a vertical line is θ = 27.33°. What are the values for the magnitudes of electrostatic force, Fq, and the ...

**Physics**

@bobpursley

**Physics**

One object has a charge of +5.0 × 10−6 C, and a second object has a charge of +2.0 × 10−6 C. The objects are 0.5 meters apart. What is the electrostatic force between them?

**College Algebra**

Pounds of nuts-cost per pound-total cost 41-$2-? x-$8-? ?-$7-? There is a chart and I have to fill in the question marks. x= 205/6 0r 34.16667

**College Algebra**

Randall wants to mix 41 lb of nuts worth $2 per lb with some nuts worth $8 per lb to make a mixture worth $7 per lb. How many pounds of $8 nuts must he use?

**Chemistry**

Calculate H2 Equation 1- CH4g+2O2g+CO2g+2H2OgH1=-890kj Equation 2- CH4g+O2g+CH2Og+H2OgH2=? Equation 3- CH2Og++O2g+CO2g+H20gH3=-518kj

**Chemistry**

Equation 1- 2Ss+3O2g+2SO3gh1=? Equation 2- 2Ss+2O2g+2SO2gh3=-594kj Equation 3- 2SO2g+O2g+2SO3gh3=-198kj Use Hess's law in your own words.

**Chemistry**

Consider this reaction N2g+O2g+2NOg H=180.5kj How much heat would be required to produce 1.300 mol NOg?

**Chemistry**

The reaction of 1 Mol of iron metal with 3 Mol aqueous HCI produces 1.5 mol H2 gas, 1 mol aqueous FeCI3, and 87.9 kj of heat. Write a thermochemical equation for this reaction

**ELA**

Yeah I get what your saying but I need a to write 2 or 3 paragraph a about what I want to know.. And I want to know the same thing you do but I don't know how to write that in a paragraph explaining!!

**ELA**

What are few questions and stuff that people or anyone would want to know about electrical engineering.... I need help writing 3 paragraphs based on that.

**Chemistry**

Calculate the number of moles of solute in each of the following solutions: Solution Moles of Solute 2.1 L of 0.21 M NH4HCO3 3.5 L of 0.28 M MgCO3

**English p3**

Traditional healers should be allowed to practice and prescribe medicines in hospitals and clinics and i agree with this topic. Speech should be in one page.

**English**

Speech about traditional healers should be allowed to practice and prescribe medicines in hospitals and clinics and I agree with this topic.

**Engineering**

What are few things that people want to know about electrical engineering??

**Journalism**

Anyone.. I am not really sure

**Journalism**

List the things that people actually want to know about electrical engineering

**life orientation**

People should stop engaging in fraud. it is not the only way to make a living. Being engaged in fraud will end you up on jail. You would loose momemts you would have with family

**Journalism**

What site

**Journalism**

I need 15 questions to ask an electrical engineer.

**History essay**

How to write a history essay based on a question with prompts?

**Math**

That's the issue I am having

**Math**

Find all of the solutions for this addition problem. Each different letter in the puzzle stands for a different digit. Letters that are the same stand for the same digit. Remember to include all of the criteria from the guidelines. ONE + ONE = TWO

**math**

seven horses are entered in a race. If two horses are tied for first place, and there are no ties among the other five horses, in how many ways can the seven horses cross the finish line?

**math**

horses are entered in a race. If two horses are tied for first place, and there are no ties among the other five horses, in how many ways can the seven horses cross the finish line?

**Geograph**

I need help writing a paragraph of why the stamp act of 1765 was not fair to the colonist.

**Geography**

Oops wrong one

**Geography**

The Stamp Act of 1765 was the first internal tax levied directly on American colonists by the British government. The act which imposed a tax on all paper documents in the colonies came at a a time when the British empire was deep in debt from the seven years war and looking ...

**george mason**

horses are entered in a race. If two horses are tied for first place, and there are no ties among the other five horses, in how many ways can the seven horses cross the finish line?

**mason**

seven horses are entered in a race. If two horses are tied for first place, and there are no ties among the other five horses, in how many ways can the seven horses cross the finish line?

**Language Arts**

Which of the following passages from the novel best illustrates the most extreme hostility between the Chinese and American communities in San Francisco?

**geography**

How coal is formed?

**precalculus**

solve log(2+x)-log(x-3)=log2 I know the answer is 8

**math**

solve log(2+x)-log(x-3)=log2

**English (research)**

How can I prove that a superhero is a monster? i.e. - Spider-man

**Data analysis**

hello hi did you figure out how to do this? ahahha help

**Math**

Find the rotation in revolutions per minute given the angular speed and the radius given the linear speed and the rate of rotation. 1. w= 2.7 rad/s 2. v=24.8 m/s, 120 rev/min 3. w= 4/3Pi rad/hr Please help me with these problems! I am a visual learner and I learn best when ...

**Math**

2.2 is my answer.

**Math**

Meredith's new scale measures in both pounds and kilograms. The information on the box says the scale has a weight limit of 200 kilograms or 440 pounds. Using this information, approximate the unit rates of kilograms per pound and pounds per kilogram, to the nearest ...

**economics**

yes

**Math/ELA**

What can I do now as a 7th grader to prepare and save for college

**Chem**

Consider the following balanced equation: 2N2H4(g)+N2O4(g)→3N2(g)+4H2O(g) Complete the following table showing the appropriate number of moles of reactants and products. If the number of moles of a reactant is provided, fill in the required amount of the other reactant, ...

**Calculus**

two small planes take off from the same airport at the same time. One travels north at 200 km/h, and the other, west at 150 km/h. If the planes fly at the same altitude, how fast are they separating after 2 hours?

**organic chemistry**

Apart from the fact that between the two structures, only cyclohexe-4-ene-cis-1,2-dicarboxylic acid has the OH group shown on the IR spectrum. In what other majors way will the IR spectrum of cyclohex-4-ene-cis-1,2-dicorboxylic anhydride differ from the IR spectrum of ...

**GEOMETRY HELP PLEASE**

The bases of trapezoid $ABCD$ are $\overline{AB}$ and $\overline{CD}$. We are given that $CD = 8$, $AD = BC = 7$, and $BD = 9$. Find the area of the trapezoid.

**History**

“Without consideration of ‘traditions’ and prejudices, it [Germany] must find the courage to gather our people and their strength for an advance along the road that will lead this people from its present restricted living space to new land and soil, and hence ...

**Precalculs**

solve using matricies x+2y+3z=7 -x+2y-z=1 -x+y-2z=-2 x= y= z= ive tried everyway I can think of please help

**History**

What was the Columbian Exchange? A. The exchange of new goods globally as a result of European exploration B. A trading post established by Christopher Columbus C. An economic system set up by Christopher Columbus in the Americas D. The trading of goods from Columbia to North ...

**History**

thank you..its B

**History**

Sir Thomas More was executed because he A. would not stand with Henry VIII against the Protestant revolt. B. would not accept Henry VIII as head of the Church in England. C. protested the corruption of the Roman Catholic Church. D. set up a utopian community based on Calvinist...

**Math**

Use the acidity model given by pH = −log[H+], where acidity (pH) is a measure of the hydrogen ion concentration [H+] (measured in moles of hydrogen per liter) of a solution. Compute [H+] for a solution in which pH = 6.2. (Enter your answer in scientific notation. Round ...

**Geometry- URGENT PLEASE HELP!!**

Medians $\overline{AX}$ and $\overline{BY}$ of $\triangle ABC$ are perpendicular at point $G$. Prove that $AB = CG$. In your diagram, $\angle AGB$ should appear to be a right angle.

**Business Stats**

Regression Analysis: Avg. Tot. Score versus %Takers, T/S Ratio Model Summary S R-sq R-sq(adj) R-sq(pred) 34.2385 79.91% 79.06% 76.83% Coefficients Term Coef SE Coef T-Value P-Value VIF Constant 1118.5 39.5 28.34 0.000 %Takers -2.547 0.187 -13.62 0.000 1.05 T/S Ratio -3.73 2....

**Math**

Mr. Jacobs budgeted $1,200 for tiles his sketch of the floor requires him to use 38 white tiles each white tile cost $12

**English**

Ok, thanks. But how do I actually write the paragraph? As to say, in the 1st sentence what should I write? and same to the 2nd, 3rd , 4th, 5th, and so on. As an example..

**English**

How do I write a paragraph response based on a book-chapter? Thanks in advance!

**Personal Finance**

To stretch your income during retirement, you could: A. skip leisure activities. B. cut your food expenditures. C. cancel your life and property insurance. D. use your skills and time instead of your money. I think its A..

**Personal Finance**

If overall interest rates in the economy rise, a corporate bond with a fixed interest rate will generally: A. increase in value. B. decrease in value. C. remain unchanged. D. become worthless. B?

**Math**

Thank you

**Math**

Terry buys a shirt for $14.99 and a pair of jeans for $39.99. If the sales tax is 8.25%, what is the total price Terry pays for the items? Can someone please show me how to work this problem?

**english**

What best completes this statement about "London, 1802"? In Lines 9 and 10 Wordsworth uses _____. personification metaphor simile allusion line9 Thy soul was like a star, and dwelt apart; line10 Thou hadst a voice whose sound was like the Sea:

**EASY Pre-Algebra**

In the following situation, determine whether you are asked to determine the number of permutations or combinations. Then do the calculation. How many ways can the four offices of chairman, vice chairman, secretary, and treasurer be filled from a club with 28 members?

**Physics**

A ball is thrown from the ground toward a cliff of height h with a speed of 30.0 m/s and an angle of 60o above horizontal. It lands on the cliff 4.00 s later. How high is the cliff? Answer: 25.5 m But having difficulty getting this answer

**Physics**

You take a trip in your car. Starting from rest, you accelerate at 1.00 m/s2 for 10.0 s, heading north. You then stop accelerating and immediately head west at a constant speed for an additional 20.0 s, at which point, you crash into a building coming to an instant stop. At ...

**Calculus**

A landscape architect wished to enclose a rectangular garden on one side by a brick wall costing $60/ft and on the other three sides by a metal fence costing $50/ft. If the area of the garden is 102 square feet, find the dimensions of the garden that minimize the cost.

**speech for history**

Traditonal africa marriage is an advantage for men only,not women

**Chemistry**

Both ethanol (CH3CH2OH, MM=46.07g/mol) and methanol (CH3OH, MM=32.04g/mol) have been considered as fuels for automobiles. Which is the better fuel, on a per gram basis, when burned with oxygen? CH3CH2OH(g) DeltaHf(KJ/molrxn) = -235.10 H3OH (g) DeltaHf(KJ/molrxn) = -200.66 H2O...

**Writing**

Please, need help. Anyone, I'll appreciated! For western history class, what did Arab culture look like before the appearance of Muhammad and Islam?

**English**

Is Mercutio a foil to the Nurse? I think they are not, but can you please check my answer? Thanks

**Math**

A girl bought mangoes at 7.50 each. There were two types of mangoes: good ones and not so good ones. She sold the good ones at 7.90 each and the not-so-good ones at 7.70 each. If she earned 34, how many mangoes did she buy?

**Chemistry**

A 26.8 mL sample of a solution of RbOH is neutralized by 15.71 mL of a 1.918 M solution of HBr. What is the molarity of the RbOH solution?

**social studies**

thx

**social studies**

what was the supreme court's ruling on the dred scott case?

**Social Studies 9**

Purpose some reasons why women were unable to keep leadership positions during the rein of terror? There is nothing about this in my textbook.

**math**

90% as a decimal is 0.9. If you multiply 0.9(the result on the test)x90 (how many questions there were) you get 81. Peggy got 81 questions right out of 90 which is 90%.