Thursday

November 27, 2014

November 27, 2014

Total # Posts: 19,590

**math**

9 + 63 = 72 using rounding which happens to be exact and I also call 9 and 63 compatible numbers since adding 9 to anything is super easy.
*August 18, 2014*

**physics**

V defined as speed out of the barrel time rising = time falling so find rise time and multiply by 2 vertical problem: Vi = V sin 30 = .5 V v = Vi - 9.8 t v = 0 at top 0 = .5 V - 9.8 t so t = .5 V/9.8 and 2 t = total time aloft = V/9.8 at max height there is no vertical ...
*August 18, 2014*

**physics**

You are welcome :)
*August 18, 2014*

**physics**

if none were added dN/dt = k N number produced per second = 10 number lost per second = k n so dN/dt = 10 - k N N is maximum when dN/dt = 0 0 = 10 - k (1000) k = .01 so we know that for this fission reaction (without the inflow) dN/dt = -.01 N dN/N = -.01 dt ln N = -.01 t + C ...
*August 18, 2014*

**probability**

first red = 8/24 second blue = 4/23 so (1/3)(4/23) = 4/69
*August 17, 2014*

**Engineering maths**

outside dimensions of deck are L and W inside dimensions of deck are 30 and 22 so Area of deck = L W - 660 so L W - 660 = 480 L W = 1140 if x = deck width Length L = 30 + 2x W = 22+2x so (22+2x)(30+2x) = 1140 multiply out and solve quadratic
*August 17, 2014*

**physics**

I think they mean total acceleration up
*August 17, 2014*

**physics**

Vi = a t = 32 * 4.1 = 131 m/s at burn out h = (1/2)32 (4.1)^2 = 269 meters at burn out then v = Vi + a t at top v = 0 0 = 131 - 9.8 t t = 13.4 seconds coasting up h = 269 + 131 (13.4) -4.9 (13.4)^2
*August 17, 2014*

**computers**

Yes, http://www-03.ibm.com/ibm/history/exhibits/pc25/pc25_birth.html
*August 17, 2014*

**computers**

As I remember Microsoft
*August 17, 2014*

**important math question**

http://archives.math.utk.edu/visual.calculus/3/newton.5/
*August 17, 2014*

**important math question**

sorry, x - y / dy/dx
*August 17, 2014*

**important math question**

Newton's method for finding zeros f(x) = x^3 -x-5 pick an x in the range, say x = 2 f(2) = 1 f'(2) = 3 x^2 - 1 = 11 mark that point (2,1) and slope of 11 through it now that slope will hit the x axis at x + y / dy/dx or 2 + (-1)/11 = 1.909 now repeat again and again ...
*August 17, 2014*

**important math question**

Did you click on the polynomial calc link? You can use Newton's method. I will give you a link in a minute. Oh, no need, this next problem is in fact Newton's method. Draw a sketch f(3) = 5 Put an x at (3,5) slope ay (3,5) = -2 f(x+dx) = f(x) + slope * dx f(3 + .02) = ...
*August 17, 2014*

**typo**

1.90416
*August 17, 2014*

**important math question**

The only real root is x = 1.0416 http://www.mathportal.org/calculators/polynomials-solvers/polynomial-roots-calculator.php
*August 17, 2014*

**trigonometry**

draw a sketch cos 68 = x/43
*August 17, 2014*

**Algebra**

Every integer is a rational number because you can divide it by one.
*August 17, 2014*

**Precalculus**

at least one typo 2Z-W=(2Zx-Wx)i+(2Zy-Wy)j |2Z-W|^2=4Zx^2-4ZxWx+Wx^2+4Zy-4ZyWy+Wy^2 =4|Z|^2+|W|^2 -4(ZxWx+ZyWy)= 625 and |Z+2W|^2 =|Z|^2+4|W|^2 +4(ZxWx+ZyWy)=25 so 625+25 =5[ |Z|^2+|W|^2| ] or 130 = |Z|^2 + |W|^2 now that last one |Z+W|^2= Zx^2+2ZxWx+Wx^2+Zy^2+2ZyWy+Wy^2] = 4 ...
*August 16, 2014*

**Precalculus**

You asked for it: 2Z-W=(2Zx-Wx)i+(2Zy-Wy)j |2Z-W|^2=4Zx^2-4ZxWx+Wx^2+4Zy-4ZyWy+Wy^2 =4|Z|^2+|W|^2 -4(ZxWx+ZyWy)= 625 and |Z+2W|^2 =|Z|^2+4|W|^2 +4(ZxWx+ZyWy)=25 so 625+25 =5[ |Z|^2+|W|2| ] or 130 = |Z|^2 + |W|^2 now that last one |Z+W|^2= Zx^2+2ZxWx+Wx^2+Zy^2+2ZyWy+Wy^2] = 4 ...
*August 16, 2014*

**mathematics**

well lets see 14 23 32 41 50 could be 23 or 41
*August 16, 2014*

**Physic - Oh well, Google might help**

http://antoine.frostburg.edu/chem/senese/101/measurement/faq/indiana-jones.shtml
*August 16, 2014*

**Physic sorry :(**

LOL, can not help with this, did not see movie !
*August 16, 2014*

**Math**

ALMOST !!! sign error - dx /[(x+dx+3)(x+3) ] divide by dx -1/[(x+dx+3)(x+3) ] now let dx -->0 -1/(x+3)^2 which any calculus text will tell you is the right answer d/dx (1/u) = [bottom*d top - top d bottom]/bottom squared
*August 16, 2014*

**Math**

oh, much more fun !
*August 16, 2014*

**Math**

sqrt 2/ 4 = .35355 which is what our table and graph said
*August 16, 2014*

**Math**

no it is one quarter of the square root of 2
*August 16, 2014*

**Math**

Now that was fun but you do the next one :)
*August 16, 2014*

**Math**

sorry 1/ [2 sqrt2) multiply top and bottom by sqrt 2 to rationalize and we get (sqrt 2) / 4 as we knew all along
*August 16, 2014*

**Math**

x y 1.0 .318 0.5 .334 0.2 .345 0.1 .349 .05 .351 .02 .353 .01 .353 .001 .35351 etc which looks much like (sqrt 2 )/4 [(x+2)^.5-2^.5]/x * [(x+2)^.5+2^.5] ----------------------------------- [(x+2)^.5+2^.5] [(x+2) -2] = ------------- x [ (x+2)^.5+2^.5] = 1/ [(x+2)^.5+2^.5] which...
*August 16, 2014*

**Math**

http://www.wolframalpha.com/input/?i=%28%28x%2B2%29^.5-2^.5%29%2Fx
*August 16, 2014*

**Math**

You are welcome.
*August 16, 2014*

**Math**

By the way since this particular function is linear, constant slope, there was no need for us to take the limit to find the derivative (slope at x is slope at any x)
*August 16, 2014*

**Math**

this is the definition of the derivative f(x+dx) = 3(x+dx)-2 = 3 x + 3 dx -2 f(x) = 3 x - 2 f(x+dx) - f(x) = 3 dx divide by dx = 3
*August 16, 2014*

**fitness**

I do not know what to say :(
*August 16, 2014*

**fitness**

Having already found differing answers to these questions online, I think you better use the ones in your text book.
*August 16, 2014*

**Algebra**

2.5 * 144
*August 16, 2014*

**fitness**

Question 3 I suppose they mean the average baby.
*August 16, 2014*

**fitness**

Please post answers when you find them :)
*August 16, 2014*

**physical**

the deaths from heart, cancer and stroke, but they add to 50% which is not on your list of answers.
*August 16, 2014*

**physical**

That same site has the answer to question 2 in a link.
*August 16, 2014*

**geometry**

Must be less than 3+5 and more than 5-3
*August 16, 2014*

**geometry**

2 2 3 3 3 1
*August 16, 2014*

**Math**

by "right" do you mean "right triangle" ? If so then tan B = b/a B = tan^-1 (b/a)
*August 16, 2014*

**calculus**

Hey, you are doing great ! These last two were harder than the ones you asked for help with.
*August 16, 2014*

**calculus**

good, that is a long one :) add, then multiply, then add
*August 16, 2014*

**calculus**

3 min = 180 seconds downstream = 5 * 180 across = 12 * 180 hypotenuse = sqrt (across^2 + downstream^2)
*August 16, 2014*

**calculus**

in the x direction 6 * 1 = 6 int the y direction 2 * -4 = -8 in the z direction 0 * 1 = 0 6 + -8 = -2 see: http://www.mathsisfun.com/algebra/vectors-dot-product.html to see how to do it with |A| * |B| * cos theta
*August 16, 2014*

**Physic**

hard to say without knowing the volume. duck it in a full cup and measure the amount of water that flows over the lip.
*August 16, 2014*

**Physics 2**

Hard to say without knowing the distances... In general F = k Q1 Q2 /|R^2| iin direction of R If horizontal length = a and vertical height = h Q is lower right Q1 is lower left Q2 is upper left Q3 is upper right R is vector from Q to one of the other 3 Rx = x component of R Ry...
*August 16, 2014*

**Algebra**

I am not sure your superscript shows up on everyone's screen. 5 (14-20)^2 /2 = 5 * 36 /2 = 5 * 18 = 90
*August 16, 2014*

**physics, mit 2.01x, mechanical engineering**

If you tried to copy and paste the drawing or sketch of this truss here, it did not work because copy and paste is not allowed here. From what you said, moment of inertia of the cross section must be increased or length of section reduced assuming you are doing Euler column ...
*August 15, 2014*

**math**

how many buggies? 21 = 9 + 3 n n = 4 4*4 = 16 21 - 16 = 5
*August 14, 2014*

**Math**

1+2+3 average is (1+3)/2 = 2 2*3 = 6 check :) so I think it is (1+31)/2 = 16 16*31 = 496
*August 14, 2014*

**math**

-2 = -1/.5 so they are perpendicular, yes, C
*August 14, 2014*

**math corrections**

profit, p = revenue, r - cost, c r = revenue = 25 g c = cost = 75 so p = 25 g - 75 so if p >/= 50 then 25 g - 75 >/= 50 so you are right. It is E.
*August 14, 2014*

**math**

4.85/4 = 1.21625 = quarterly percent 11 years = 44 quarters (1.0121625)^44 = 1.7022 3,500 * 1.7022 = 5957.70 so agree. I do not see any list of staetements
*August 14, 2014*

**mathematics**

x+6
*August 14, 2014*

**math corrections**

I agree with your answer, C and have no idea why it is called incorrect.
*August 14, 2014*

**math corrections**

1, 5c 2 10 c 3, 15 c 4, 25c 5 30C 6 35 c 7 40 c 8 50 c 9 55 c 10 60 c 11 65 12 75 c 13 80 c 14 85 c 15 90 c
*August 14, 2014*

**math**

4000/7 = 571.4 so we need a little more than 571 572 will do 572 * 7 = 4004, check :)
*August 14, 2014*

**math**

5 28 = 300 + 28 = 328 6 43 = 360 + 43 = 403 sum = 731, agree
*August 14, 2014*

**Finance**

If your in county prices go up so you must pay more of your coins for a banana, then your coins will buy fewer of my bananas and is worth fewer of my coins which can still buy as many bananas as they did last year.
*August 14, 2014*

**fundinjobo high science**

H2 is 2 grams/mol so we have 40 mols of H2 which is 80 mols of H for each mol of H we get 1/3 mol of NH3 so we get 80/3 mols of NH3 NH3 is 14+3 = 17 grams/mol (80/3)mols * 17 grams/mol = 453 grams NH3
*August 14, 2014*

**math**

y = 14 t - 4.9 t^2 if you do not know physics or calculus you must complete the square to find the vertex of the parabola. 4.9 t^2 - 14 t = -y t^2 - 2.857 t = -(1/4.9) y t^2 - 2.857 t + 1.429^2 = -(1/4.9)y+2.04 (t-1.429)^2 = -(1/4.9)[ y - 10 ] vertex at height 10 meters and ...
*August 14, 2014*

**history**

http://history.howstuffworks.com/revolutionary-war/hartford-convention.htm B. mainly ports for international trade. (Boston, Philadelphia, New York, Charleston, the ports in Va and MD ....... Hey, Google this stuff !
*August 14, 2014*

**history**

....... from Albany to ______ Oh well :(
*August 14, 2014*

**math**

What are you talking about? 15,000 (1 + 0.10/12)^12n for 6 years 15,000(1.008333)^72 = 15,000*1.8176 = $ 27,263.91 for 12 years 15,000 (1.008333)^144 = $49,554.73 etc
*August 14, 2014*

**math**

4 s = 20 s = 5
*August 14, 2014*

**maths probably typo but all right here is your cost**

I suspect you men .10 or 1.0 times 8 per mile not $10 per (1/8) mile but since you used 10 I will go along with $80 per mile c = 1.8 + 80 m c(4.5) = 1.8 + 80 (4.5)
*August 14, 2014*

**Maths**

.75 fruits = orange or .75 f = oj .25 fruits = apples or .25 f = a oj - 10 = .5 a so .75 f - 10 = .125 f .625 f = 10 f = 16 answer now check 12 + 4 = 16 yes 12 - 10 = 2 2 = half of 4 yes
*August 14, 2014*

**maths parentheses? might as well be Martian**

I can not decipher your text right off for example (36/25)^(3/2) or [36/(25)^3]/2 or what, no hope unless you use parentheses properly
*August 14, 2014*

**Math**

if y = a x^n then dy/dx = a n x^(n-1) so if y = 2400 x^1 - 2 x^2 then dy/dx = 2400 (1) x^(1-1) - 2 (2) x(2-1) or dy/dx = 2400 x^0 - 4 x^1 which is dy/dx = 2400 - 4 x
*August 14, 2014*

**math**

try volume Vnew = (x+2)(x+2)(x+2) big mess try area Anew = (x+2)(x+2) = x^2 + 4 x + 4 not this for sure try that perimeter thing how many edges? 4bottom +4top +4verticals = 12 edges 12 * 2 = 24 !!! winner
*August 14, 2014*

**maths**

suspect you mean 0.10 per 1/8 mile or 0.80 per mile c(n) = 1.80 + .8 n c(4.5) = 1.80 + .8 (4.5)
*August 14, 2014*

**maths**

I told you.
*August 14, 2014*

**maths**

surface area = area of base and top (same for both) + height*2 pi r so not the same and not twice volume = area of base * height ah ha, twice if you double height
*August 14, 2014*

**Statistics**

combinations of 15 taken six at a time 15!/ [6! (15-6)!] 15! /(9! 6!) 15*14*13*12*11*10 / (6*5*4*3*2) 7*13*11*5
*August 14, 2014*

**maths**

2.25 times volume = area of base * height height the same base 1.5*1.5 = 2.25
*August 14, 2014*

**Physics**

change in potential energy = m g h = work done = 2180 Joules/second * t
*August 14, 2014*

**Physics**

r omega^2 = 9.81 m/s^2 r = (6.9/2)*1000 = 3450 m so omega^2 = 9.81/3450 omega = .0533 radians/s (that is about 118 seconds /revolution or about 2 minutes per revolution)
*August 14, 2014*

**Physics**

force * time = change in momentum = m v
*August 14, 2014*

**physics**

x displacement = 50 cos 90 + 50 cos 245 = 0 -21.43 y displacement = 50 sin 90 + 50 sin 245 = 50 -45.3 = 4.68 displacement = sqrt (-21.4^2+ +4.68^2) = 21.9 meters x is negative and y is positive so quadrant 2 tan angle above x axis = tan^-1 y/-x = tan^-1 4.68/21.43 = 12.3 deg ...
*August 13, 2014*

**math**

25 + 12*15 = 205 .12 * 205 = 24.60 saved
*August 13, 2014*

**Algebra**

either way. (a*b)/c = (b/c)a = a b / c
*August 13, 2014*

**algebra**

Please, please, try to use standard notation Do you mean (3-s)^(1/3) = 3 ??????? if so raise both sides of the equation to the third power (3 - s)^1 = 3-s = 27 s = 3 - 27 s = -24
*August 13, 2014*

**mathematics (word problems)**

.5 x + .25 x = monitor + modem .25 x remains so .25 x = 200 + 150
*August 13, 2014*

**whoops**

(m-1/4)(.8) = 3 - 1.2
*August 13, 2014*

**math**

0.10 per 1/8 mile = 0.8 per mile miles = m (m - 1/4 ).10 = 3.00 - 1.20
*August 13, 2014*

**math**

volume of box = 4*3*2 = 24 ft^3 volume of brick = 8/12 *4/12 * 2/12 = 2/3 * 1/3 *1/6 = 1/3 * 1/3 *1/3 = 1/27 ft^3 24/ (1/27) = 648
*August 13, 2014*

**Math**

You try first.
*August 13, 2014*

**math**

17 * 10^-6 mm .0 0 0 0 1 7 move that dot 6 places right and you get 17
*August 13, 2014*

**English**

http://www.sparknotes.com/lit/flies/section12.rhtml
*August 13, 2014*

**Geometry: Area and Volume Math**

I mean volume of sphere :)
*August 13, 2014*

**Geometry: Area and Volume Math**

length in cm or meters or feet or elbows or thumbs area in cm^2 or m^2 or ft^2 or elbows^2 or thumbs^2 volume in cm^3 or m^3 or ft^3 or elbows^3 or thumbs^3 areas = multiple of two lengths volumes = multiples of three lengths of course those lengths might be the same for ...
*August 13, 2014*

**Geometry: Area and Volume Math**

length * width * height 6 * 6 * 6 = 6^3 = 216
*August 13, 2014*

**math**

sin Angle = 10/20 = .5 as we all know sin 30 degrees = .5
*August 12, 2014*

**help AGAIN**

Hopefully curiosity leads to an explanation. Hopefully sincerity leads to trustworthiness.
*August 12, 2014*

**physics**

time for phase 1 = 7/9.5 = .737 hr time for entire trip = 23/22 = 1.045 hr time for 16 km = 1.045 - .737 = .308 hr speed for 16 km = 16/.308 = 52 km/hr
*August 12, 2014*

**chemistry**

P V = n R T V = n (R T/V0 so volume is proportional to number of mos if P and T are constant we need three mols of H2 for every mol of N2 so there is exactly the right amount of each for every mol of N2 we will get 2 mol of NH3 so for every mL of N2 we will get 2 mL of NH3 so ...
*August 12, 2014*

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