Thursday

September 18, 2014

September 18, 2014

Total # Posts: 1,220

**Calculus**

If f(x)= -4x^2+7 and x≤0, what is the equation of the inverse function? The answer is supposed to be f^-1(x)= -[√(7-x)]/2, but this is what I did: x=-4y^2+7 -4y^2=x-7 y^2=(x-7)/-4 y= √[(x-7)/-4] Did I do something wrong? By the way, for the original function...
*March 10, 2014*

**math**

There are eight shelves. How many soup cans a grocery clerk stack if the bottom shelf has 21 cans and each additional shelf has 2 fewer soup cans than the previous shelf?
*March 6, 2014*

**math**

using the interest formula A=P(1+r/n), solve for the indicated variable. solve for P
*March 5, 2014*

**Math**

Eric has two rock samples. One has a mass of 600 grams and the other has a mass of 1 kg. He recorded the total mass as 7 kg. What did he do wrong? What is the correct answer?
*March 4, 2014*

**College Cultural Geography**

"Respect for traditions that violate human rights is taken by Western universalism as tantamount to disrespect for their victims." What about this part?
*March 2, 2014*

**College Cultural Geography**

Can someone explain what this paragraph is talking about? I do not understand it. "But Western universalism, again, has two faces: it also promotes the principles of liberty and equality throughout the world. It is not possible to proclaim global human rights, on the one ...
*March 2, 2014*

**physics**

A 400 g marble block has a specific heat of 860 J/kg C deg. If the block is placed in 700 ml of water, the marble changes it temperature by 17 Celsius degrees. Since the specific heat of water is known to be 4186 J/kg C deg, what is the temperature change of the water. (The ...
*February 19, 2014*

**physics**

A wave travels at 575 m/sec in a dense media. The wave is observed to The length of the media is 95.8 cm. When the wave is reflected at the end, its phase is reversed (an upward motion becomes a downward motion.) What is the frequency of the resonant wave in this media?
*February 19, 2014*

**physics**

The speed of sound in air varies with the temperature and humidity of the air. In dry air at 20 degrees Celsius, the speed of sound is approximately 343 m/sec. A closed tube resonates with a node at each end for a sound wave in air. What is the length of tube you would choose ...
*February 19, 2014*

**Physics**

1200kg car moving at 9.72m/s runs into and sticks to a parked 1000kg car. The collision takes 0.15s and after the crash the cars wheels lock and they skid to a stop on the u=0.40 road. what is the distance travelled before skidding to a stop?
*February 17, 2014*

**Thesis Statement**

Weak, because you should mention specifically what is it about your experience with teaching children that you want to write about.
*February 17, 2014*

**Calculus**

Thanks so much Reiny! I never thought of adding the cost to the equation, but now I know.
*February 17, 2014*

**Calculus**

A holding pen for fish is to be made in the form of a rectangular solid with a square base and open top. The base will be slate that costs $4 per square foot and the sides will be glass that costs $5 per square foot. If the volume of the tank must be 50 cubic feet, what ...
*February 17, 2014*

**math**

If an apartment complex will need painting in 3 1 2 years and the job will cost $25,000, what amount needs to be deposited into an account now in order to have the necessary funds? The account pays 12% interest compounded semiannually.
*February 16, 2014*

**physics**

How far from Earth will Venus be today?
*February 16, 2014*

**Astronomy**

What five object were found in the sky on February 5, 2014 at 9 pm.
*February 15, 2014*

**Astronomy**

a.According to the Starry Night program, which constellation the Sun was actually in at the instant of a person birth on August 12, 1953. b. What was the right ascension of the Sun on the moment a person was born on August 12, 1953. c. What constellation is this position in?
*February 13, 2014*

**maths**

a grocey man sells 300 apples at Rs 50 per dozen. he sells 200 apples from it at Rs 50 for 10 apples. what will the price per apple for the remaining apples to get an overall profit of 12%
*February 12, 2014*

**math**

donna brings 32 slices of apples and oranges to the party. there are 3 times as many oranges than apples. how many apples are there
*February 6, 2014*

**biostatistics**

Seventeen people has been exposed to a particular disease. Each one independently has a 40% chance of contracting the disease. A hospital has the capacity to handle 10 cases of the disease. What is the probability that the hospital's capacity will be exceeded? a- .011 b- ....
*February 5, 2014*

**statistics**

Height of children in kindergarten described by normal mode with mean 39.2 inches and standard deviation of 1.9 inches. What percent of children can expect to be less than 38 inches tall?
*February 1, 2014*

**Pre-Calculus**

Actually I figured out that you use both, and ended up with 16x^7(x^2-9)^7 + 6x^5(x^2-9)^8. but I don't understand how that simplifies to 2x^5(x^2-9)^7(11x^2-27)?
*January 29, 2014*

**Pre-Calculus**

Find dy/dx if y= x^6[(x^2-9)^8]? So the answer is supposed to be 2x^5[(x^2-9)^7](11x^2-27), but I don't understand how to get it. Do you use product rule, chain rule or both? thanks
*January 29, 2014*

**Math**

An athletes long jump rounded to the nearest metre was 8 m. Whar are the longest and shortest lengths the jump could have been in decimals to the hundredths ?
*January 29, 2014*

**Math**

An athletes long jump rounded to the nearest metre was 8 m. What are the longest and shortest lengths the jump could have been in decimals to the hundredths.
*January 29, 2014*

**geometry**

Calculate lengths of ap,bp,cp. A(0,0) B(0,2k) C(2h,0) P(h,k)?
*January 22, 2014*

**algerbra**

sasha researched the size of zoos in her state. she found that the zoo in the north part of the state is almost twice as large as the zoo in the south. she also found that the zoo in the south part of the state has 200 fewer than twice the number of animals as the northern zoo...
*January 9, 2014*

**math**

find the slope of the linethat passes through the given points (4,6) and (4,4)
*December 19, 2013*

**reimbursement methodologies**

which of the following was the governments way of controlling skyrocketing health care costs?
*December 18, 2013*

**Pre-Calculus**

y= ((2-3x^(1/x))/(2+3x^(1/x)) Is the horizontal asymptote y= 1 or y= -1?
*December 18, 2013*

**Pre-Calculus**

Is it possible to factor x^3 - 9x^2 + 24x - 20 and solve for x by hand? I tried using the grouping method and got x^2(x-9) + 4(6x-5) but how can I continue solving for x? If I use a calculator I get x= 2 and 5 but is it possible to find this by hand? thanks
*December 16, 2013*

**math**

Evaluate definite integral of (2x+2)(x^2 + 2x -5)^5dx upper limit 2 and lower limit 1
*December 15, 2013*

**music**

I need help I'm about to take my Comprehensive Final Exam on Foundations of Music A STEP BY STEP APPROACH TO MUSIC THEORY. I'm so confused I don't want to fail my test I failed the last two I'm afraid of failing. Please help me.
*December 10, 2013*

**Math**

Oh I think I know what I did wrong now
*December 7, 2013*

**Math **

Cassandra is two thirds as old as Jeremy. Three years ago she was half as old as Jeremy. How old are Cassandra and Jeremy? I got this question wrong and was wondering what I did wrong. This is what I did. Now 3 years ago Cassandra| C | C-3 Jeremy | J | J-3 C=2/3J C-3=1/2(J-3...
*December 7, 2013*

**Pre-Calculus**

Solve the equation 2x + 5y - 3z = -1. Write the general solution as a matrix equation. I did some guessing and ended up getting this much: [x]= [-1/2 _ _ ] X [1] [y]= [ 0 1 0 ] X [s] [z]= [ 0 0 1 ] X [t] however I still can't figure out the last two values in the first row
*December 6, 2013*

**Pre-Calculus**

I still don't really understand how to do it... I did some guessing and ended up getting this much: [x] [-1/2 _ _] [1] [y]= [0 1 0] X [s] [z] [0 0 1] [t] however I still can't figure out the last two values in the first row.
*December 6, 2013*

**Pre-Calculus**

[x] [...] [1] [y]= [...] X [s] [z] [...] [t] to align it better I put dots in the blanks...and I think s and t are free variables that be be any real number
*December 6, 2013*

**Pre-Calculus**

Solve the equation 2x + 5y - 3z = -1. Write the general solution as a matrix equation. [x] [ ] [1] [y]= [ ] X [s] [z] [ ] [t] I'm supposed to fill in that blank in the middle, but I don't understand how to solve this if I'm only given one equation. please explain
*December 6, 2013*

**Pre-Calculus**

if not, then can you show me how to do this with the substitution method or something?
*December 4, 2013*

**Pre-Calculus**

Consider the chemical reaction aC2H6 + bCO2 + cH2O → dC2H5OH, where a, b, c, and d are unknown positive integers.? The reaction must be balanced; that is, the number of atoms of each element must be the same before and after the reaction. For example, because the number ...
*December 4, 2013*

**Pre-Calculus**

wow that was a silly mistake I didn't see the x next to 500 and thought I could just subtract it from 1000 thank you!
*November 20, 2013*

**Pre-Calculus**

A piece of equipment has cost function C(x)=50x^2 + 1000 and its revenue function is R(x)= 500x - x^2, where x is in thousands of items. What is the least number of items that must be sold in order to break even? 50x^2 + 1000 = 500x - x^2 50x^2 + x^2 + 500= 0 51x^2 + 500 = 0 ...
*November 20, 2013*

**Pre-Calculus**

Wow, I didn't realize that finding (x-2) was already finding the equation of the line. Thanks!
*November 19, 2013*

**Pre-Calculus**

The graph of f(x)= (x^2 - 11x + 18)/(x-9) consists of a line and a hole. Find the equation of the line and the coordinates of the hole. I really have no idea how to do this. I tried factoring it and ended up with (x-2), but I don't know how that helps me. please help
*November 19, 2013*

**Pre-Calculus**

oh yeah thanks I forgot that the reciprocal had to be negative
*November 19, 2013*

**Pre-Calculus**

What is the equation of the line passing through (4, 2) and perpendicular to the line passing through the points (9,7) and (11,4)? Here's what I did: (7-4)/(9-11) = -3/2 y-2= (-2/3)(x-4) y-2=(-2x/3) + (8/3) y = (-2x/3) + 14/3 but the answer key says that it's y=(2x/3...
*November 19, 2013*

**Pre-Calculus**

thanks...though I asked for (-3,-1).
*November 17, 2013*

**Pre-Calculus**

Find the slope of the tangent line to the curve 2(x^2+y^2)^2=25(x^2−y^2) at the point (−3,−1)? Here's what I did: 2(x^4 + y^4) = 25(x^2-y^2) 2x^4 + 2y^4 = 25x^2 - 25y^2 8x^3 + 8y^3(dy/dx) = 50x - 50y(dy/dx) d/dx(8y^3 + 50y) = 50x - 8x^3 d/dx = (50x-8x^3...
*November 17, 2013*

**Pre-Calculus**

thanks
*November 14, 2013*

**Pre-Calculus**

no it's actually 1x and 1xy. It's not division.
*November 14, 2013*

**Pre-Calculus**

Find the slope of the tangent line to the curve √(1x+2y) + √(1xy) = 8.24 at the point (2,8)? I know you have to use implicit differentiation, but the radicals keep making me mess up algebraically. Is the changing the radicals to exponents the fastest way? please ...
*November 14, 2013*

**Pre-Calculus**

nevermind I made a mistake it's p(x)=-1x/10 + 465
*November 13, 2013*

**Pre-Calculus**

A manufacture has been selling 1050 television sets a week at 360 dollars each. A market survey indicates that for each 20 -dollar rebate offered to a buyer, the number of sets sold will increase by 200 per week. p(x)=1x/10 + 465 How large of a rebate should the company offer ...
*November 13, 2013*

**Pre-Calculus**

Thank you all so much!
*November 12, 2013*

**Pre-Calculus**

When you do implicit differentiation, how does D = √(x^2 + 8x + 12) turn into dD/dt = [(x + 4)(dx/dt)]/√(x^2 + 8x + 12)? please explain...I don't even understand where the (x+4) comes from. D means distance, but that's irrelevant
*November 12, 2013*

**Physics**

laf is standing on a sheet of ice that covers the football stadium parking lot in Buffalo, New York; there is negligible friction between his feet and the ice. A friend throws Olaf a ball of mass 0.400kg that is traveling horizontally at 11.5m/s . Olaf's mass is 65.2kg. If...
*November 12, 2013*

**physics**

In the construction of bridges and skyscrapers, gaps must be left between adjoining steel beams to allow for the expansion and contraction of the metal due to heating and cooling. The temperature of a sample of iron with a mass of 10.0g changed from 50.4oC to 25.0oC with the ...
*November 3, 2013*

**Science**

a wagon that has a mass of 8kg? If the net force on a wagon is 4N, what is the wagon’s acceleration?
*November 3, 2013*

**Pre-Calculus**

thanks
*November 3, 2013*

**Pre-Calculus**

How is -16/(4x+6)^5 and -1/(2(2x+3)^5) equivalent? I think -1/2(2x+3)^5 is the more simplified version of the two, but I just can't figure out how -16/(4x+6)^5 simplifies to -1/(2(2x+3)^5). please explain
*November 3, 2013*

**Pre-Calculus**

thank you
*October 31, 2013*

**Pre-Calculus**

Let f(x) = [(√x)-7]/[(√x)+7]. What is f'(x)? What is the easiest way to find the derivative of this? Should I remove all the radicals and use quotient rule, like f'(x)= ((x^0.5) + 7)(0.5x^-0.5) - ((x^0.5)-7)(0.5x^-0.5) / ((x^0.5) + 7)^2 Is this right? How ...
*October 31, 2013*

**math**

find an equation of the line passing through the pair of points. write the equation in Ax+By=C (-9,7), (-10,-4)
*October 29, 2013*

**math**

find an equation of the line with the given slope that passes through the given point. write the equation in the form Ax+By=C M=3/2, (7,-3)
*October 29, 2013*

**Ancient History Art**

Can the extravagance and costs, both of money and lives, be justified in the opulent architecture commissioned by "divinely empowered" individuals of ancient cultures? Name a comparable example from today's society.
*October 27, 2013*

**math**

ok 35020/1.03=34000 ....but where did the 1.03 come from?
*October 23, 2013*

**math**

Find last years salary if after a 3% pay raise this years salary is $35,020
*October 23, 2013*

**Pre-Calculus**

this is weird...but thanks!
*October 19, 2013*

**Pre-Calculus**

Determine the derivative at the point (2,−43) on the curve given by f(x)=7−7x−9x^2. I know that the answer is -43, but I was wondering if it was just a coincidence that the derivative at the point (2,−43) is -43, or is there a reason why -43 is the same...
*October 19, 2013*

**Pre-Calculus**

Thank you very much
*October 18, 2013*

**Pre-Calculus**

Yeah, that was a stupid mistake... But now I have another question. Isn't the final answer supposed to be in −1/(ah+b) form? Why is my answer 1/(196+14h) still positive? Did I do something else wrong?
*October 18, 2013*

**Pre-Calculus**

Let f(x) be the function 1/(x+9). Then the quotient [f(5+h)−f(5)]/h can be simplified to −1/(ah+b). What does a and b equal to? So I understand the overall concept, and did f(5+h) = 1/(14+h) and f(5) = 1/14. Then to subtract the two, you get the common denominator ...
*October 18, 2013*

**Pre-Calculus**

The Hotel Ventor has 400 rooms. Currently the hotel is filled. The daily rental is $ 600 per room. For every $6 increase in rent the demand for rooms decreases by 7 rooms. Let x = the number of $ 6 increases that can be made. What should x be so as to maximize the revenue of ...
*October 14, 2013*

**Pre-Calculus**

Nevermind, now I see that all the question asks for is the y-intercept. Why didn't I see that before...
*October 14, 2013*

**Pre-Calculus**

It has been found that the supply of golf clubs varies linearly with its price. When the price per item was $ 76.00 ,32 items are supplied; When the price was $ 90.25 , 70 items are supplied. What is the lowest price above which golf clubs will be supplied ? So I know the ...
*October 14, 2013*

**geometry**

find measurement angle bac db and dc are paralell, da intersects bc, angle a is 65 degrees so i multipied by two and came up with the answer 130 degrees, is this correct? thanks
*October 14, 2013*

**Pre-Calculus**

I tried and got 3.371880575, but I think I'm still wrong...
*October 9, 2013*

**Pre-Calculus**

You are given a pair of equations, one representing a supply curve and the other representing a demand curve, where p is the unit price for x items. −p+0.0208333333333333x+2=0 and p = √(57-x) What is the market equilibrium for x? I know I'm supposed to set both...
*October 9, 2013*

**Pre-Calculus**

Actually I think you used the wrong function. The 1st one is the demand, not the second.
*October 8, 2013*

**Pre-Calculus**

You are given a pair of equations, one representing a supply curve and the other representing a demand curve, where p is the unit price for x items. 466p+90x−2390=0 and 484p−22x−978=0 Determine the revenue function. Revenue function R(x)=? I got (-90x/466...
*October 8, 2013*

**Pre-Calculus**

For the function f(x)=3x^3−42x Compute the difference quotient [f(x+h)−f(x)]/h,h≠0 I checked my work like 3 times and still got [(-2x^3)+(3hx^2)+(3xh^2)+(h^3)-(42h)]/h Is it wrong?
*October 7, 2013*

**Pre-Calculus**

Oh yeah I forgot it meant that P = 0 thanks
*October 6, 2013*

**Pre-Calculus**

The function is P=−11x^2+346.5x−2612.5
*October 6, 2013*

**Pre-Calculus**

The profit in dollars in producing x items of some commodity is given by the equation P=−11x2+346.5x−2612.5. How many items should be produced to break even?(If there are two break-even points, then enter the smaller value of x. Your solution may not be an integer...
*October 6, 2013*

**Pre-Calculus**

thanks I figured out what I did wrong
*October 6, 2013*

**Pre-Calculus**

Find the unknown in the following equation. If there are more than one solution, then separate the solutions with a comma. (−8y−4)^2+10=14 y=? I keep on getting y=-0.5, is that correct?
*October 6, 2013*

**Pre-Calculus**

thanks!
*October 6, 2013*

**Pre-Calculus**

The Hotel Bellville has 400 rooms. Currently the hotel is filled . The daily rental is $ 250 per room. For every $ 14 increase in rent the demand for rooms decreases by 5 rooms. Let x = the number of $ 14 increases that can be made. What should x be so as to maximize the ...
*October 6, 2013*

**Pre-Calculus**

thanks
*September 30, 2013*

**Pre-Calculus**

oh ok. But if I wanted to find how long it takes the ball to come back to the ground then I would have to factor it right?
*September 30, 2013*

**Pre-Calculus**

Sorry, the equation is −16t^2+72t+364
*September 30, 2013*

**Pre-Calculus**

A ball is thrown up at the edge of a 364 foot cliff. The ball is thrown up with an initial velocity of 72 feet per second. Its height measured in feet is given in terms of time t, measured in seconds by the equation h=−16t2+72t+364. How high will the ball go? To get how ...
*September 30, 2013*

**Pre-Calculus**

So the answer is C(x)= 2574 + 3x?
*September 30, 2013*

**Pre-Calculus**

I solved that and got C(x) = 2580 + 3x, but apparently it's still not the right answer...
*September 30, 2013*

**Pre-Calculus**

A local photocopying store advertises as follows. " We charge 14 cents per copy for 150 copies or less, 6 cents per copy for each copy over 150 but less than 230, and 3 cents per copy for each copy 230 and above. " Let x be the number of copies ordered and C(x) be ...
*September 30, 2013*

**Pre-Calculus**

Then what would the cost be for 150<x<230? I don't think there's a fixed cost for this either, but I don't think it'd be correct to write C(x) = 6x.
*September 30, 2013*

**Pre-Calculus**

A local photocopying store advertises as follows. " We charge 14 cents per copy for 150 copies or less,6 cents per copy for each copy over 150 but less than 230, and 3 cents per copy for each copy 230 and above. " Let x be the number of copies ordered and C(x) be the...
*September 30, 2013*

**Pre-Calculus**

Oh, ok, so it's not equivalent. I get it now. It is 2.2. Thanks!
*September 28, 2013*

**Pre-Calculus**

Wait, Steve, I think that what you wrote: A(t) = 11000 - (11000-10995.60)*t/4.4 is equivalent to what I wrote: A(t) = -4.4t + 11,000 but when I solve mine, why do I keep on getting 0.5 instead of 2.2?
*September 28, 2013*

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