Sunday

April 20, 2014

April 20, 2014

Total # Posts: 16,179

**math**

Tn = a + a+d + a+2d .... + a +(n-1) d T3 = a +2d T8 = a + 7 d so a + 2d = 2 (a+7d) a + 2d = 2 a + 14 d a + 12 d = 0 a = -12 d sum of first 25 = (n/2)[ 2a +(n-1)d ] = (25/2) [ -24 d + (24) d ] LOL !!! = 0

**Math- NOT CALCULUS**

Hey, I told you use completing the square to find the vertex, boring. 2 n^2 - 84 n = - p - 45 n^2 - 42 n = -p/2 - 22.5 n^2 - 42 n + (21)^2 = -p/2 -22.5 + 441 (n-21)^2 = - (p/2 - 418.5) (n-21)^2 = - (1/2) (p - 837) so 21 taxis making 837

**algebra**

-9 x + 10 y = -9 10 y = 9 x - 9 y = (9/10) x - 9/10 slope = 9/10 well, the y axis intercept is y when x = 0 10 y = -9 y = -9/10

**finance**

That is beyond my pay grade Carol. You need a financial software package. Google "yield to maturity" The semiannually confuses the issue but I am not sure it matters much and perhaps you can use the 6% You have to assume you reinvest the interest. You have to figure ...

**Physics**

distance engineer moved = 500 m = .5 km average speed = (84.2 +16.4)/2 = 50.3 km/hr (during constant acceleration you can use the average of first and last for the distance and time) time = distance/speed = .5km / 50.3 km/hr = .00994 hours * 3600 = 35.8 seconds

**Chemistry**

p v = n R T n and R the same so P1 V1/T1 = P2 V2/T2 T1 = 18 + 273 T2 = 273 P1 = 980 Torr P2 = 760 Torr V1 = .35 V2 = ?

**Physics**

charge has no effect on mass

**VARIATION- ALGEBRA 2**

Hey Amy, you should be able to do these now.

**VARIATION- ALGEBRA 2**

x = k v^2 30 = k (625) k = 30/625 x = (30/625)(1600) = 76.8 ft

**Algebra 2- Translations**

LOL - I have no idea what is going on with this function

**Physics**

m g down mu m g friction force F = m a mu m g = m a a = mu g = .4 (9.81) = 3.92 m/s^2 a = change in speed/time change in speed = v average speed during stop = v/2 distance = average speed * time 5 meters = v/2 t so t = 10/v a = v /(10/v) = v^2/10 so v^2/10 = 3.92 v^2 = 39.2 v ...

**math**

3 / 7

**Math**

P(20) = -2(400) + 84(20) - 45 if you do not know calculus, find vertex of parabola by completing square. I am assuming calculus. 0 = -4 n + 84 n = 21 at maximum so Pmax = -2(21^2) + 84(21) - 45 21, been there, did that -45 when n = 0

**Algebra 2- Variation**

I guess you mean y = k x^2 sqrt z 49 = k (4)(5) k = 49/20 y = (49/20)(1)(4) = 49/5

**Math**

what your teacher did was say g =-10 m/s^2 F = m g = m a so a = -10 m^s^2 then v = Vi - g t = Vi - 10 t h = Hi + Vi t - (10/2)t^2 Vi = 20 v = 0 at top = 20 - 10 t so t at top = 2 h at top = 60 + 40 - 20 = 80

**wrong, typo **

but I think I see the problem you mean H = -5 t^2 + 20 t + 60 when t = 0, the height is 60. That is the height of the cliff if t = 2 h = -5(4) + 20(2) + 60 = -20 +40 + 60 = 80 when dH/dt = 0 or vertical speed is 0 it stops going up 0 = -10 t + 20 t = 2 seconds to top (that is ...

**Algebra 2- Variation**

You are welcome :)

**Algebra 2- Variation**

w = k r/p^2 25 = k (5)/16 k = 5*16 = 80 so w = 80 r/p^2 16 = 80 r/64 r = 16*64/80 = 12.8

**Pre - calculus**

(cos/sin)/(1/ cos^2)+(cos/sin)/(1/sin^2) cos^3/sin + cos sin cos^3/sin + cos sin^2/sin cos (cos^2 + sin^2)/sin but cos^2 + sin^2 = 1 so cos/sin or cot x

**Physics**

so in my head I am supposed to have stored the Young's modulus of steel ? delta L/L = tensile stress/E or delta L = F L /(E A) F = 4700 N A = (pi/4) .005^2 meters^2 L = 1.2 meters E = you look it up

**Math**

1. no, x = 15

**math**

12 + 10 = f/2 22 = f/2 f = 44

**Physics**

F = G M m/r^2 = m Ac so Ac = G M/r^2 G = 6.67 * 10^-11 M = 6 * 10^24 kg Copy this 4175 miles = meters into a Google search box and get r = 6.72*10^6 meters and 90 minutes is 5,400 seconds

**math**

combinations of n people r at a time = n!/[ r! (n-r)! ] n = ? r = 2 36 = n!/[ 2 (n-2)! ] 72 = n! /(n-2)! 72 = n (n-1) the rest cancels 72 = n^2 -n n^2 - n - 72 = 0 (n-9)(n+8) = 0 n = 9

**Physics**

There is no horizontal force. Therefore the horizontal velocity REMAINS CONSTANT v = - g t = -9.81*5 = 49 m/s down

**Math**

h = 37 t - t^2 at t = 10 h = 370 - 100 = 270 dh/dt = 0 at top = 37 - 2t t = 37/2 = 18.5 seconds to top h = 37(18.5) -18.5^2 = 342 when is h = 0 again? t(t-37) = 0 t = 37 seconds (which of course is 18.5 times two)

**Math**

do you mean (sinT - 1/cosT) or do you mean (sinT-1)/cosT

**physics**

F = G M m /d^2 6.67*10^-11*7.8*10^23*2.5*10^4/57.8*10^16 =2.25 * 10^0 = 2.25 N

**Physics**

for a more elaborate analysis see http://www.braeunig.us/space/propuls.htm read starting around equation (1.11)

**Physics**

initial momentum = 4.6*10^4 * 6.3*10^3 = 29 * 10^7 kgm/s no external forces so that is the final momentum final momentum = ship mass m *7.84*10^3 + exhaust momentum exhaust mass = (4.6*10^4 - m) what is the exhaust speed? I assume that 4.86 * 10^3 is relative to the space ship...

**physics**

(1/2) m u^2 = m g (Hup - Hdown) so u = sqrt(2*9.81*.954) u is horizontal speed, does not change How long in the air? Well, how long to fall .256 m ? .256 = 4.9 t^2 solve for t, time in the air distance horizontal = d = u t

**Physics**

work in = potential energy stored = (1/2) k x^2 double x, four times the energy stored so four times the work in.

**Math!**

You do not need help which ones start with 9 for example? you have a 97, 99, 92, 91, 94, 95, 93, 97 so 9| 1 2 3 4 5 7 7 9

**Physics**

initial momentum = 3.7 * 5 = 18.5 kg m/s mass after crash = 3.7 + 2.0 = 5.7 kg so 18.5 = 5.7 u u = 3.25 m/s which is the horizontal speed until it hits the floor. NOW I DO NOT BELIEVE that your table is 6.9 meters high so I will just outline the rest How long to fall h meters?...

**math**

slope = (7/3) y = (7/3) x + b -3 = (7/3)(-3) + b -3 = -7 + b b = 4 so y = (7/3) x + 4 or 3 y = 7 x + 12

**Math**

initial price = p marked up is 1.1 p then marked down is .9(1.1) p = .99 p

**SCIENCE**

Your stomach

**Intermediate Algebra**

p = 2 L + 2 w 192 = 2 L + 2 w L = 2 w so 192 = 2 (2w) + 2 w 192 = 6 w w = 32 etc

**math**

360/10 = 36 degrees for each piece 3 * 36 = 108 degrees total for the three slices

**Math.**

the first one I am sure is a. Scroll down and look at where this was posted a few minutes ago.

**phy**

how long to fall 50 meters? d = 4.9 t^2 t = sqrt(50/4.9) = 3.19 seconds so how far did it go horizontally? d = u t = 10 * 3.19 = 31.9 meters

**Science**

probably, depends how long it is sitting there and how cold it was when it came out of the freezer and what its specific heat and heat of fusion is and what its shape is, a long tube will melt faster than a sphere of the same mass as you know.

**Science**

NOT a !!!!! c = 3 * 10^8 m/s like period NOT b !!!! either can have any old amplitude for c and d , go look at that chart in the link I gave you earlier

**ALGEBRA! URGENT.**

3 | 7 8 9 ---> 37, 38 , 39 4 | 1 3 7 ---> 41 , 43 , 47 5 | 2 4 ---> 52 , 54 and a. is: a. 37, 38, 39, 41, 43, 47, 52, 54 so I do not think c is right. I am not educated enough in this to look at the rest.

**Physics**

3/4 = .75 hour at 70 ---> 52.5 1/6 = .167 hr at 95 ---> 15.8 1/2 = .5 hr at 55 ---> 27.5 20/60 = .333 hr at 0 --> 0 total time = 1.75 hours total distance = 95.8 km so 95.8 km / 1.75 hr = 54.7 km/hour

**typo**

w = -13 is the other choice, no good

**Intermediate Algebra**

w(w+5) = 104 w^2 + 5 w - 104 = 0 w = [ -5 +/- sqrt (25 + 416)] /2 w = [ -5 +/- 21 ]/ 2 w = 8 or w = 13 L = 8+5 = 13 then A = 8*13 = 104 w = 13 is too big so 8 by 13

**Algebra**

24 x^3 - 3 3 (8x^3 - 1) now 8 x^3 = (2x)^3 perfect cube and 1 = (1)^3 perfect cube and a^3 – b^3 = (a – b)(a^2 + ab + b^2) note a^3-b^3 not +

**Typo**

speed downstream = 12 + c

**Algebra**

Tom can row at the rate of 12 kilometers per hour in still water. He rows upstream for two hours and returns in one hour and twelve minutes. Find the rate of the current. D=r*t R=12 km per hour T= two hours --------------------------- speed upstream = 12 - c speed downstream ...

**Algebra**

Dukes chain saw requires a ration of oil to gas 1 to 40. How many ounces of oil should he add to one half gallon of gas? 8 oz = 1 cup 2 cups = 16 oz = 1 pint 2 pints = 32 oz = 1 quart 4 quarts = 128 oz = 1 gallon By the way " a pint is a pound the world around" :) so...

**Algebra**

A Piece of rope that is 63 meters long is cut into three pieces such that the second piece is twice as long as the first and the third piece is three meters longer than the second. Find the length of each piece. 2x+3x+x=63 --------------------------- need to be more orderly fi...

**Algebra**

Erin has three more dimes than nickles and twice as many quarters as dimes. she has a total of $5.05 How many of each type of coin does Erin have 5.05= 2q-d-3d-n -------------------- but they have different values nickels = n, value = .05 n dimes = (n+3), value = .10(n+3) quar...

**social studies**

inte så mycket Rus

**social studies**

I suspect Scandinavia. Sweden settled Delaware first but I wonder why the Dutch in New York are left out. http://www.colonialswedes.org/History/History.html

**Algebra**

You are welcome :)

**Algebra**

1.08 x = 1620

**Algebra**

same deal with the mowers 1/6 + 1/2 = 1/t 2/3 = 1/t t = 1.5

**Algebra**

Joe does 1/6 room/hour Theresa does 1/10 room per hour together they do (1/6+1/10) = 5/30 + 3/30 = 8/30 = 4/15 of a room /hour so 15/4 hours/room (about 4 hours)

**mathematis**

I guess the first term is -4 and the difference is a = 3 Term n = term 1 + (n-1) a Term n = -4 + (n-1) 3 for example Term 3 = -4 + 2(3) = 2 , good, that works so Term n = -4 + (n-1)3 = 74 3(n-1) = 78 n-1 = 26 n = 27

**Algebra 1**

slope = 4 any other line with slope = 4 will do for the opposite side for example y = 4 x + 53178 then we need two lines perpendicular to those slope = -1/original slope = -1/4 so y = -.25 x + b again any two b values y = -.25 x + 3.14159 and y = -.25 x - 3.14159 or whatever

**algebra**

(-1 -(-1) ) /(-3-6) = 0/-9 = 0 so the slope is zero (of course) it is the line y = -1

**Science**

Look at the chart on the right of that link and the legend beneath it.

**Science**

Ever see a low frequency radio antenna :) ? there are radio waves kilometers long. see: http://en.wikipedia.org/wiki/Electromagnetic_spectrum

**finance**

I forgot to mention that the 30 year pays more per year than the 10 year because in the 30 years inflation may make the income worth much less.

**finance**

Of course as you can see, wealthy people often do not spell well.

**finance**

Well, one of the characteristics of the market is that some people will buy each of them depending on what their priorities are. A retiree with wishes for a very safe income stream might choose the 30 year treasury. A young person who is willing to take a risk for higher retur...

**finance**

yearly income versus safety versus inflation. Why do you think Greece is paying 5 times as much as France? Why do you think a 30 year bond pays more per year than a ten year bond from the same treasury ?(usually) Why do you think an inflation indexed bond might pay negative in...

**Science**

You can not copy and paste here. You could post it to a web hosting site like Scribd and then tell us how to find it (you can not post a link either) but that is a pain.

**Science**

We can not see your picture or diagram or whatever. low frequency is long wavelength is low energy. I have no idea which is brighter. Perhaps one is not in the visible spectrum?

**math**

huh? A /(1 + r/n) = P

**math**

10/20 = 1/2 = .5 meters = 500 cm in (ii) do you not want the WIDTH of the real house If so 80 cm = .8 m .8 m * 20 = 16 meters wide

**science(check answers)**

You have BOTH motion AND position

**science(check answers)**

NO!!!! total mechanical D

**science(check answers)**

I agree. in #7 motion is kinetic and position is potential (for example k x^2 or mgh) so together is total mechanical

**Physic assignment**

momentum before = 1.5*8 + 2*3 momentum after = 1.5*x + 2*7.29

**Cultural Diversity**

I am glad Ms Sue answered these. I looked at them and just shook my head.

**Trig**

tan 37 = h/x tan 58 = h/(5-x) x tan 37 = (5-x) tan 58 x (tan 37+tan 58) = 5 tan 58 x = 5 tan 58/ (tan 58 + tan 37) then h = x tan 37

**Math help**

4 x^2 - 8 = 0 x^2 - 2 = 0 (x-sqrt 2)(x+sqrt 2) = 0 x = sqrt 2 or x = - sqrt 2

**Geometry**

interesting two 5 , 12 , 13 right triangles in there 5 + 12 = 17

**math**

x</= 500 room rent = r = 400 + i x = 500 - (8/4)i cash = [ 500 - (8/4)i ] [400 +i] cash = c = (500-2i)(400+i) c = 20,000 - 300 i - 2i^2 dc/di = 0 for max or min = -300 - 4 i d^2c/di^2 = -4 so max i = -300/4 = -75 for max x = 500 -2(-75) = more rooms than we have so we can n...

**Math**

10 - 3 = 7 18 + 2 = 20 so 7 x + 20

**my mistake !**

then -12 + c = 3 c = -15 No, +15 !!!! put in y = 11 at x = 1 to get d 11 = -1 -6 -15 + d d = 33

**calculus**

I assume you mean y or f(x) = -x^3 +bx^2 +cx + d if so y' = -3 x^2 + 2 b x + c and y" = -6 x +2 b at x = -5 , y' = 0 -75 -10 b + c = 0 at x = 1 , y' = 0 -3 + 2 b + c = 0 so 2 b + c = 3 -10 b + c = 75 -----------------subtract 12 b = -72 b = -6 then -12 + c = 3...

**?**

Sorry, I do not know what that means.

**math**

(5282+4689+3029+6390) / 4 =4847.5 = 4848

**physics**

I assume that a Mg is a "megagram, a term I have never heard before. In that case we have 4*10^6 grams which is 4,000 Kilograms 4,000 * 30 = 120,000 kg m/s south

**physics**

F = G M m/R^2 = m v^2/R so v^2 = G M/R G = 6.67 * 110^-11 M = 6 * 10^24 Re = 6.38*10^6 meters Ra = 6.38*10^6 + .418*10^6 Rb = 6.38*10^6 + .731*10^6

**physics 1**

F = G Mm/R^2 = m v^2/R v^2 R = G M = 6.67*10^-11 * 5.98*10^24 v^2 R = 39.9 * 10^13 v T = circumference = 2 pi R so R = v T/(2 pi) R = v [1.77*10^4/(2 pi)] R = 2.82*10^3 v so v^3 (2.82*10^3) = 39.9 * 10^13 v^3 = 14.1 * 10^10 = 141 * 10^9 v = 5.2 * 10^3 v = 5,200 m/s

**log**

2 = e^.09 t ln 2 = .09 t = .6931 t = 7.7 years

**Trig**

2 sin 3x = 2[ 3 sin x-4 sin^3 x] = 6 sin x - 8 sin^3 x 4 sin 2x = 4[ 2 sin x cos x ] = 8 sin x cos x so 6 sin x - 8 sin^3 x + 8 sin x cos x 2 sin x [ 3 - 4 sin^2 x + 4 cos x ]

**Algebra**

for similar objects volume goes up proportional to cube of the length dimension. Of course people are not always mathematically similar in shape but never the less: ------ my answer is b

**Physics**

NONE !!!! work is force IN THE DIRECTION OF MOTION times distance

**Math help**

1. (Y+5)(Y-7)=0 if Y = -5 then you have (-5+5) (something) = 0 or 0 * something = 0 so 0 = 0 so Y = -5 IS A SOLUTION same deal for Y = 7 (something)( 7 - 7 ) = 0 sure enough y = 7 Is a solution so I claim in general if (something ) (a x + b) = 0 then x = -b/a IS a solution for...

**Chemistry**

Compare the physical and chemical properties of acids and bases.

**Algebra 2**

(5,10),(10,7)= y=(5/3)x-(17/3) m = (7-10)/(10-5) = -3/5 so your m = 5/3 y = (5/3) x + b x --> 15/2 y --> 17/2 so through (15/2 , 17/2) 17/2 = (5/3)(15/2) + b so 17/2 = 25/2 + b b = - 8/2 = -4 y = (5/3) x - 4 agree with your second answer this time

**Algebra 2**

(1,4),(6,-6)= y=(1/2)x-(3/4) m = (-6 -4)/(6-1) = -10/5 = -2 so your m = +1/2 check x ---> (1+6)/2 = 7/2 y ---> (4-6)/2 = -1 so (7/2 , 1) 1 = (1/2)(7/2) + b 4/4 = 7/4 + b b = -3/4 y = (1/2) x - 3/4 I like your first answer

**Algebra 2**

Perhaps I am not being clear. There is no reason the original pair of points would be on the perpendicular bisector of the line between them. In fact they better not be there.

**Algebra 2**

(-5,6),(1,8)= y=-3x+1 m = (8-6)/1+5) = 2/6 = 1/3 so yes, your slope is -3 y = -3 x + b now midpoint x --> (-5 + 1)/2 = -2 y --> (6+8)/2 = 7 so yes the middle is at (-2 , 7) 7 = -3(-2) + b 7 = 6 + b b = 1 so yes y = -3 x + 1 THe original points are NOT on the bisector.

**Math**

150 + 50 + 150 + 50 = 400 meters = 0.4 km .4 km/lap * n = 1 km n = 1/.4 = 2.5 laps

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