Saturday

April 19, 2014

April 19, 2014

Total # Posts: 1,391

**Math-Triangles**

Sara, I understand what you're doing, but I think the question wasn't put clearly. Neither of the triangles here is right-angled. The two triangles are similar: their sides have the same ratio. We know one is 2*7:3*7:4*7 and the other is 2*9:3*9:x and we need to find x.

**Math-Triangles**

I answered this below, but you didn't specify that the triangles are similar in the original question. That means that the clue is in my original answer.

**MATH**

Noting that ACK is not the same as KAC, You can choose from 5 letters for your first Then you can choose from 4 letters for your second. Finally you can choose from 3 letters for your first So you can choose in 5 * 4 * 3 ways.

**9th grade (math)**

answered below, for "kevin"

**physic**

OK, now I see the whole question. No, your number is right but you need to check your direction. Take two steps east, 2 steps north, 2 steps south. You are now two steps ____ of where you started.

**physic**

If your question was: "julianna walked 45 meters WEST, 45 meters south , and 45 meters north" then you are correct!

**Math**

Yes, absolutely! Try this: 18 : 27 : x = 2*9 : 3*9 : x 14 : 21 : 28 = 2*7 : 3*7 : 4*7 Clearer now?

**Math**

I don't understand the question. You have only one missing length for two triangles? I do note that the ratio of sides in the two cases is 2:3:(1/3)x 2:3:4 Just considering triangle 1, x could be anything less than 45 (bonus question: why?). Maybe you want x so that the tw...

**Math**

Only back for a few minutes. Then I have to go help a grown-up whose "homework" is even harder than yours. :-)

**Math**

Suppose the price today is 100. In one year, that'll be 106, which is 100 * 1.06. The next year, it'll be 6% up again, which is 106 * 1.06 = 112.36 The next year after that, it'll be 6% up again, which is (106 * 1.06) * 1.06 = 112.36 * 1.06 = 119.10. You seeing a p...

**math**

The best way to do question 1 is to draw a graph of each. Draw your x, y axes, then find two points on each of the lines, then use a ruler to draw the line that they're both on. Which two points? Any two will do, but it's easier to draw if they're not too close tog...

**operating system**

I only have time for a short answer at the moment. You need to sort by the PPID parent process ID first, so that you can trace each process back through its parents. Everything traces back to 0 eventually. Example: Process 6017's parent is 6003. 6003's parent is 1. 1&#...

**Math**

You're welcome!

**Math**

Let's estimate the problem first. Handy to check our thinking. There are 3 tiles per foot, right? And there are a bit over 10 feet to tile, at 3 tiles per foot, so our answer is going to be near 30 tiles. If you multiplied 1/3 by 10, you'd get about 3 as an answer, so ...

**Math**

(Yes I did, but I'm back. Hey, it's Saturday!) Yes! Not that the _current_ average is .2857, just that the average of the new games that are added on is .2857. If Harry batted exactly .308 in the next 28, his average would stay the same, at .308. If he bats lower, the ...

**Math**

Forget his current average for a minute. Now, what batting average does 8 hits in 28 make? (Divide 8 by 28.) We don't know how that .308 was made up, but we know that if 8/28 is greater than .308, he's batting better than his past average, so the average will go up. Eq...

**Math**

No, the sale price of the house doesn't matter. It could be 6,000 or 6,000,000; we don't care for this purpose. What we know is that for every 6 dollars Stephen borrows, he has to pay 7 back. What we don't know, that we would like to know, is how long Stephen has t...

**Math**

Interest is usually shown as a percentage rate per year, but since we don't know the number of years, we can't calculate it here. Mortgages are usually for 10-30 years. If it was one year, which would be very very short for a mortgage, the rate would be 1/6, since he h...

**Math**

I presume that by mortgage here is meant to total value to be paid back for the loan. When the bank lends you money, you have to pay back more than you borrowed, the extra being the interest. We don't know how much Stephen borrowed, but we know he has to pay back 7/6 of th...

**Math**

The reason you didn't think of that is just that you haven't had enough practice yet. :-) Keep plugging at it, and you'll be doing these things without even having to think about them!

**Math**

Good question! Really good question, since you're thinking of the more general case. You can't use the same trick there; I'm afraid you'll have to calculate. The standard way, that will always work, is to find a common denominator of the two fractions, so that ...

**Math**

Glad I could help. :-)

**Math**

Right! If it's bigger than one, the number on top is larger. Now, is 19/6 greater or less than one? Is 4/27 greater or less than one? So without calculating anything, you can show that the two fractions cannot be equal.

**Math**

I like this question! It's simple, but should make you think, and there are many ways to approach it. I'd hate to deprive you of the thinking experience, but here are some questions for you. What does it mean for a statement about numbers being equal to be "true&q...

**Science**

Search for "population ecology" and "population biology". You might find what you're looking for there. I think "population ecologist" may be the term you're looking for.

**science**

answered below

**science**

1800g = 1.8kg How many 1.8 kg are in 80 kg?

**math (algebra)**

Take the next one then. Step by step. 9x = 5y + 3 Parallel, but going through (-2, 4). x is -2. y is 4. It must be 9x = 5y + something 9*-2 = 5*4 + something. What is the something?

**math (algebra)**

That's OK. First you solve it. Then you put it into the form you need. Point slope form just means moving y to the left hand side, and everything else to the right. Consider: x + 5y = 47 Subtract x from both sides: 5y = 47 -x Divide by 5 y = 47/5 - x/5

**math (algebra) -oops**

I typoed, and it might confuse you. Sorry. 5*8 is 40, or course, not 47. x + 5y = something 7 + 5 * 8 = something 7 + 40 = something = 47 So a line parallel to x+5y=2, containing (7,8) is x+5y=47.

**math (algebra)**

The key point to know is that: if the new line is parallel, then the coefficients of x and y will be the same (The coefficients are the numbers that x and y are multiplied by). So, taking the first one, any line parallel to x+5y=2 will be of the form x + 5y = some_number x + 5...

**algrbra 2**

Divide the difference in the y coordinates by the difference in the x coordinates to get the slope.

**Algrbra 2**

This is quite straightforwatrd. x is 15, so 15 - 5*y = -25 so what is y?

**math**

I think maybe what's being asked is to get an equation with B on the left-hand side. A=(1/2)BH multiply both sides by 2 2A=BH divide both sides by H 2A/H = B so B = 2A/H

**calculus - identities**

sec(y)=1/cos(y) tan(y) = sin(y)/cos(y) Low consider left and right hand sides: LHS = 1/cos(y) - cos^2(y)/cos(y) RHS = sin^2(y)/cos(y) Now you've got everything over a common denominator, look at the top of each side, and you should see your way through.

**7th grade science**

Aristotle had the (very wrong) idea that things could move only as long as something was pushing them. This no doubt seemed reasonable in Earth conditions, before quantitative science, when just about everything that moves is pulling against gravity or friction. In a vacuum, y...

**intro to software development**

If it's any comfort, I don't quite know what they're asking either, "Processes or capabilities" could mean almost anything. I have a suspicion I'm telling you much more than you need to know. If I were writing one, I'd identify: data capture (proc...

**calculus**

Differentiate to find the max height. Velocity is 64 - 32t. Max is at s'(t) = 0, when velocity is zero s'(t)= 64 - 32t = 0 so it peaks at t=2. From that you can get the height. You now need to find s(t) = 0, so solve 64+64t–16t2 = 0 That will give you the time, an...

**calculus**

The slope of the tangent at that point will be the same as the slope of the parabola, by definition. How do you get the slope of the parabola at that point? Differentiate it. What is the differential of 4x^2–6x+6? Now plug in x=5 to your answer, and the arithmetic gives y...

**Math- Graphing Calculator Use**

I'm sorry, but I'm not sure anybody will be able to help with that information. Different calculators do stats, especially, in different ways. If you specified the exact model you're using, maybe somebody reading this would have the same one, and know how it works,...

**Calculus**

Well, the derivative of sin is cos, and the derivative of cotan is cosec^2, both of which should be in your standard list of derivatibes. Knowing that, you can just write down the answer.

**math **

4 seconds PLUS how many seconds in a minute? multiply that by 36 PLUS how many seconds in a minute? multiply that by how many minutes in an hour and multiply again by 23 That is, 23 * 60 * 60 + 36 * 60 + 4 For a check on your answer, it'll be a five-digit number like 8???4

**Calculus**

I can't find an integer n for which this is true. Consider f'(x) = 1/(2sqrt(x+6)) =1/2sqrt(52) at point x=46 You can take a factor of 4 out of that, =1/4sqrt(13) but you're still left with the irrational sqrt(13). You can't get an integer out of it unless x+6 i...

**physics**

The flash and the sound happen at the same time, but both the light and the sound have to travel to you, at different speeds. For fun, or extra credit, you could calculate how long the light takes to travel 8000m, but it's small enough that we can ignore it, especially giv...

**Math**

The average is the total score divided by the number of tests. All scores are integers, so the total score is an integer. The number of tests is an integer. What is the smallest total score that, when divided by an integer, would give 4.6?

**english**

I can think of a four letter word that begins with f. It would work even better if the first sentence were "The weather will be _____ today"

**math**

Given what?

**pre-calculus**

That's solvable easily with calculus, not sure whether you're supposed to be using it given your heading: C'(x) = 4.9(2)x - 617 = 9.8x -617.4 at its minimum, 9.8x = 617.4

**geometry**

Both have four sides. Both have pairs of adjacent sides equal. A kite's opposite sides don't have to be equal, but a rhombus must have all sides equal.

**geometry**

a) So you're looking at a Right Angled Triangle (RAT) with the two short sides being 4 and 25. What does Pythagoras say about the other side, which must be the hypotenuse? b) This is the same question, except with 6 on the shortest side instead of 4.

**Programming**

Glad I could help, especially in a case like yours where you clearly could do the job yourself, but just hit a snag. Good luck with it!

**Programming**

Given the short deadline, and that I'll be away for a while, I hacked nastily into your code, to produce something that runs all the way through, I think. I want to emphasise just how ugly this is, and that it needs a lot of work to be a worthy project! But it runs, and if...

**Programming**

I'll be away until tonight. How long do you have for this project?

**Programming**

OK, doing what I said last is really easy. Just move the two displays abve the loop, and actually draw the board instead of just returning it, like: myGame.getPrompt(); myGame.getRules(); while(myGame.winner() == 0 && !myGame.placeMarker()) { System.out.println(myGame.drawBoar...

**Programming**

I think you want a String rather than a char. Here's what I did: 1. I made a little batch file to recompile and rerun, containing javac TicTacToe.java jar cvf TicTacToe.jar TicTacToe.class javac -cp .\TicTacToe.jar Lab2.java java -classpath . Lab2 I don't know whether ...

**Programming**

Just home and had a quick look. My two immediate thoughts: 1. You need to write getCurrentPlayer() in TicTacToe so that you can get the whole thing to start running, from where you can get a handle on what it is doing. 2. I still don't think the instructions I/O should be ...

**Programming**

Nice to see you back, Tim. I'll be away from the forum until tonight, but somebody else may help in the meantime. To help them help you, you could post your thinking, given your current code. Where are you stuck? What doesn't seem to be working that you think should be...

**Chemistry**

After 0.6523 g of is heated, the residue has a mass of 0.3423 g. Calculate the % H2O in the hydrate.

**math**

two equations : n+d=42 .05n+.10d=3.85 or 5n+10d=385

**3rd grade**

if you round the number to the tens place, it is 460 if you round the number to the hundreds, it is 500 could the number be 468 and why

**Math**

a. (13-2)/32 = b. @1000 it had 11/32. @20000 it had 5/32. So after 19,000 it lost 6/32. It needs to lose another 3/32 to be "worn out". You should be able to see the number of miles from that.

**math**

Oh. If it's any comfort, I have no idea how writing sentences embodying equations could be proven, either.

**math**

The question wants you to figure out what number replaces X. 7 = x + 5 7 = ? + 5. What number replaces x, or the question-mark? You're going to write: x = (some digit, which is your answer) Proving is easy. Just write 7 = x + 5 down again, but this time replacing x with yo...

**math**

"maximum: 8, range: 6" gives you your minimum number, so pencil that in, and 8 at the other end of course to make your maximum. Now, if you know what mode and median mean, you should be ready to write in some 6s, and spread about the same number of lower digits.

**math**

Well, we're going to need three lots of some unknown number plus 4. Let the three be bags. Since we're near Halloween, let's say some unknown number of pieces of candy get divided equally into 3 bags. Then let's say somebody adds 4 pieces to each bag. Can you w...

**Math- fractions and decimals**

"62 and a half" is 62.5, or 62 1/2, or 125/2. That's all fine. But you talked about a hundred chart. I wonder whether you mean what 62.5 is as a fraction of a hundred, which is the same as asking what 62.5% is as a fraction. Does your 100 chat show 50 as being 1/...

**Algebra**

I'm totally with you on y=8, but the best way to check your answer is to substitute the value back in. Now try y=2/3: Is |2/3+3| + 5 = 2(2/3) ? Is 11/3 + 15/3 = 4/3 ? I think you took a wrong turn at: "Now, the two equations are 3=y-5 and 3y+3=5." You can't a...

**Algebra**

The perimeter is two lengths + two widths, and that has to be more than 70. 2L + 2W > 70 We know that the length is 19, so 2L = 38. 2W + 38 > 70 2W > 70 - 38 Now pick a width that makes that true. There are lots of them to choose from: a million will do. :-)

**Programming**

OK! I suggest when you get your client ready you start a new question to keep it on the front page, since I don't think anybody looks beyond the front page much. I didn't really expect to see a response down here, but I was curious so I checked.

**Programming**

Tim, this forum doesn't seem to allow indenting; that's why your code didn't show. You can paste your code if you remove the leading spaces. I did get your code. But, given that, I'm not quite clear what you want to know. By "fill in the blank", do yo...

**Computer Science Java**

A Boolean variable is a variable, like an int or a string, but whose value is either "true" or "false". Try this little lump of code, and vary d1 and d2 values, to see the effect: int d1 = 1 int d2 = 1 boolean snakeeyes; boolean doubles; boolean boxcars; sn...

**Math Analysis**

4. "I got the square root of 7x. Is this right?" Nearly, but not quite. Careful with your sqrt signs. f(x)=sqrt(x) g(x)=6sqrt(x) f(x)+g(x) = sqrt(x) + 6 sqrt(x) = 7 sqrt(x), not sqrt(7x) 16. This is much easier on paper! Consider your constants. You have sqrt(2) on t...

**math anaylsis**

g takes x to x-3. That is, start with x, then g(x) will be three less. 5 -> 2, 11-> 8, 1 -> -2. Right? f squares x, so f(5)=25. Similarly, 3-> 9, 8 -> 64, and so on. f(g(x)) just means "do g on x, then do f on the result". If you start with x=5, then g...

**programming**

I'm also not clear what is being asked, exactly, but at least it's not just a cut-and-paste question. Steve, what exactly do you need to do, and within what terms? Do you need to create a flowchart modelling currency conversion logic using some specific software, or fl...

**Physics**

A passenger on a bus moving with uniform velocity lurches forward when the bus stops suddenly. Explain? I do not understand this

**Algebra**

If it depends on something else, it's dependent. If it doesn't depend on something else, it's independent. Does the time of day depend on the air temperature? Does the air temperature depend on the time of day?

**math**

Do read the earlier two first. At the end of hour five, which we'll call t5, speed @t5 = 100 km/h It's been accelerating at 3km/h, so at 4 hours speed @t4 = 100 - 3 = 97 km/s and at 3 hours speed @t3 = 97 - 3 = 94 km/s You can work it back from there.

**math**

This is like the car problem. At the start, t0, the stone has a speed of zero. t0 = 0 m/s The acceleration is (10 meters per second) per second, so after one second the speed is 10 m/s. t1 = 10m/s After another second, we add on another 10m/s to the speed t2 = 20 m/s At the th...

**math - corr**

I used a shorthand that was wrong in this question, and it might confuse you. When I say t0 = 103 m/s what I should have said, to be clear, was speed at t0 = 103 m/s and so on.

**math**

We start counting when it's moving 103m/s. (And incidentally, that's pretty fast for a car. Formula 1, maybe?) Each second after that, it moves 1m/s faster than it was before. So if we call time by seconds, as we often do in these things, we call the start, after zero ...

**ap calc**

Draw the pool as a rectangle. Now draw a rectangle around that, such that each side is equally distant from the sides of the pool. This represents the sidewalk around the pool. The area of the pool is 12 * 18 = 216 sq.ft. If the sidewalk were 3 feet wide everywhere, the width ...

**Algebra - oops typo**

b^2 - 4ac 1 - (4)(2)(-1)

**Algebra**

Doublecheck the expression within the square root, and watch your signs. b^2 - 4ac 1 - (4)(1)(-1)

**Finance. **

Start with 10, finish with 20 after 1 year you have 10*x after 2 years 10*x*x after 3 years 10*x*x*x 10 x^3 = 20 x^3 = 2

**Finance. **

I just answered a very similar question from Kim right below. The method to solve this is the same, but you can make up your own numbers: say, 10,000 at the start and 20,000 at the end.

**finance**

I like this question :-) Let's assume interest is compounded annually. After one year, the value will be 10,477.03 * x, where x is 1 + (interest rate implicitly divided by 100). After two years, it will be 10,477.03 * x * x, because we increase it by the same percent again...

**Algebra**

Well done! You got it right. But I think you may have missed a turn in the simplification. The simplification is largely a matter of taste, but also laziness - the less you have to write to use your result in the next stage of a problem, the better :-) You started with: (10 +/...

**Programming & Algorithm**

I'm not exactly sure what (1) is asking. General considerations? An exemplar? Anyway, a stack has only two operations: push something in; pop something out. You will need space in which to store the items on the stack. Start with the items. What data types will you be stor...

**Maths**

Is this using current British coinage, or pre-decimalisation? There is a quite famous problem by Dudeney about this, but it uses old coinage - farthings and suchlike. The book "Amusements in Mathematics by Henry Ernest Dudeney" is available ibn Project Gutenberg, if ...

**math**

Magic, you need to post a new question, rather than follow on an existing thread. I'm not sure, but I think the question means that the _answer_ after subtracting 1 is 114. If so, then start by asking yourself what number leaves 114 when you subtract 1 from it. Got that? N...

**marketing**

Thanks for the kind words :-)

**marketing**

Look up what the 4 Ps are. Got that? OK. Now consider something _you_ bought recently. It's likely that it'll be easier to write about something large and unusual you bought, like a pair of skis, than something small and common, like a fizzy drink, though both will wor...

**visual basic**

I just read your question again, and I now think that, given an input string, you want to find the first non-zero digit in it. Though again, I could be wrong. So if the input is "A046", you want "4", and if it's "0.0029x" you want "2"...

**visual basic**

Perhaps the most useful tip you can know in learning to program, though you won't find it in a book, is to ask for help, giving _all_ information about the problem, whether you think it's useful of not! :-) You've posted the problem code. This is good. You haven...

**System analysis**

The hardware vendor will say it's a software problem. The software company will call it a hardware problem. The department manager will have somewhere else to be. The sysadmin/BOFH will sigh and mutter "PEBKAC" as he walks past. The experienced project manager al...

**math**

This one's kind of pretty. I first thought we'd be into sin and trig country, but we don't have to. But you have to see it in a diagram. Draw lines for the lamppost and the woman, and a line from the top of the lamppost just over the woman to the ground. You should...

**Alg**

I don't think (2z)^(1/2)/4z^4 can be correct, since y has disappeared. Take it in steps, by distributing th power: (y^(1/4)*Z^4)^(-4/5) = (y^(1/4))^(-4/5)(*Z^4)^(-4/5) Now, what's the rule for raising powers? As for (3-2SQRT2)(SQRT6-5) I don't really get it to be v...

**Math**

You've done the hard part; you're almost there! You just lost sight of the simple bit. x = 2/(2a+1) we need to find a when x = 10 10 = 2/(2a+1) Now find a

**algebra**

y=mx+c m= -1/6 y=-(1/6)x+c The point (-6,9/7) must be on that line: use it to find c by plugging in x and y like 9/7=-(1/6)(-6)+c So what's c? So now we have the equation of the line, we need the value of the point on that line where x=12. Plug in 12 instead of x in the eq...

**Physics check **

A person has a reasonable chance of surviving an automobile crash if the deceleration is no more than 30 "g's" (recall that g = 9.8 m/s2). Calculate the force, in N, on a 68 kg person accelerating at this rate. 30"g" x 9.8 294 ms^2 f=ma 294x68 =19,992N

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