# Posts by Damon

Total # Posts: 29,823

**math - calculus help!**

You could use a fancy formula for volume of a cone and differentiate it to find dV/dh but if you just draw a picture you can see that the area of the surface * dh is the added volume for added dh

**math - calculus help!**

radius/depth = 7/24 what is radius when depth = 10? 7/24 = r/10 r = 70/24 = 35/12 now the change of volume with depth h is the surface area area * dh = dV pi r^2 dh = dV pi r^2 dh/dt = dV/dt = 12 ft^3/m pi (35/12)^2 dh/dt = 12 dh/dt = .449 ft/min

**Pre calc**

Good, you have two different ways now :)

**Pre calc**

slope = (20-13)/(4-3) = 7 also for any (x,y) slope = (y-20)/(x-4) so 7 = (y-20)/(x-4) 7 x - 28 = y - 20 so y = 7 x -8

**THANK YOU DAMON**

You are welcome :)

**Social Studies**

a.They conquered inland kingdoms, which they turned into a trading empire. --------------- The big advantage the Portuguese had over Arabs etc in the Indian Ocean was big ships with big guns. They did not try to march inland. India was a civilized country with real armies, not...

**Social Studies**

Yes, maybe b then c

**Social Studies**

It was particularly the various competing Christian missionaries that made the Japanese mad, and they were very angry about what happened in the Phillippines. The Dutch were allowed to hang out in a Nagasaki trading post because they did not try to convert people or push them ...

**Social Studies**

Particularly this excerpt: "Japan had been closed to the outside world for 250 years. When foreign people entered Japanese waters, even if they were shipwrecked by accident, they were interned in jails and some of them were killed (Lubor 33). The reasons for the Japanese ...

**Social Studies**

Ah yes, this is short and sweet http://willamette.edu/~rloftus/perry.html

**Social Studies**

I am looking for a link for question 2

**Social Studies**

no, no

**Social Studies**

Now for question 2, perhaps we better look at the start of American-Japanese relations. Did you read about only the Dutch being allowed there before that fleet arrived?

**Social Studies**

here is a wiki for Goa: http://www.google.com/search?q=goa+india&ie=utf-8&oe=utf-8

**Social Studies**

Well, I suppose I could give you some link to a wiki or something, but first think about it. The Portuguese ended it all in India long this after with Goa. Can you imagine a little country like Portugal marching around India ? They were sea farers

**Social Studies**

In question 1, remember we are talking about the Portuguese, not some tea company.

**Social Studies**

Ah, what do you think? The answer to question 2 is petty dramatic and amazing.

**Pre calc**

y = m x + b y = -(3/2) x +3/4 or 4 y = -6 x + 3

**History**

Well, my choices would be: 1. Prince Henry the Navigator, Bartolomeu Dias, Vasco da Gama .... so D 2.I would say B 3. See question 1.

**Math**

65*50 = 6500/2 = 3250 ft^2 so 1625/3250 $/ft^2

**American Government**

County responsibility is now chiefly law enforcement (sheriff and county jail) and registry of deeds and such. However it still exists and the towns and cities have not take over all county responsibilities.

**American Government**

Although our ounty government has been largely eliminated over the last decade, we still have a sheriff etc. Our town governments operate much like our city governments, although often having a Board of Selectmen instead of a City Council. Both towns and cities are often run ...

**American Government**

http://en.wikipedia.org/wiki/Essex_County,_Massachusetts

**Physics**

I think it is a dip and v^2/R = 0.15*9.81

**Physics**

density = 1000 kg/m^3 is easier :) You do not say if you want gage pressure or absolute pressure I will assume gage rho g h = 1000*10*25 =2.5 *10^5 Pascals or N/m^2 if you want absolute pressure add one atmophere or about 1*10^5 for a total of 3.5*10^5 Pascals

**Physics**

You already said the speed of the boat through the water was 2 m/s The speed over the land is 2-.8 = 1.2 m/s

**physics**

v^2/R = g or it loses contact m g(h-D) = .5 mv^2 v^2 = g R = .5 g D so m g(h-D) = .5 m *.5 g D =.25 mgD h-D = .25 D h = 1.25 D

**Math**

anything^0 = 1 so x^3/x^3 = x^0 = 1 y^6/y^6 = y^0 = 1 so 1

**asthmatics**

assuming it is the height that is 9.5 outside volume = 23 * 15.5 * 11 inside volume = 20 * 12.5 *9.5 now subtract the inside from the outside

**maths**

Thank you rabin for entertaining the math tutors :)

**Chemistry**

(750-726)/(20-10) = 2.4 (800-750)/(40-20) = 2.5 (880-800)/(70-40) = 2.7 (960-880)/(100-70)= 2.7 slope increasing a bit but 2.7 seems a reasonable guess slope = (x-960)/(150-100) (x-960)= 50(2.7) x = 960 + 135 = 1095

**calculus**

http://www.mathsisfun.com/calculus/differential-equations-homogeneous.html LOOK at the example at the end :)

**Physics**

This might help: http://www.slideshare.net/ahmedqadoury/periodic-and-aperiodic-sounds-2

**Physics**

I am sorry I can not because if you do a Fourier transform on even a spike you can express even an impulse as a sum of periodic signals. However there are articles on non-periodic vibrations in the technical literature. I question if they are really that but anyway take a look...

**math, algebra**

120 + 7 x = 11 x so 4 x = 120 x = 30

**Matt**

2.54 cm/in L in cm = L in inches (2.54 cm/in) so 2.54 times as many centimeters as inchess

**Science**

MASS IS CONSERVED! Until you get to Einstein and Special relativity, the total mass is CONSTANT. .015 + .050 = .065 kg

**Math**

time = t vf t = 260 vp t = 320 so 260/vf = 320/(vf+15) 320 vf = 260 vf +260(15) 60 vf = 390 3 vf = 39 vf = 13 km/hour

**SAT Math Question?**

L --- 1/3 job/hr S ---1/5 job/hr together 1/3 + 1/5 = 8/15 job/hr (8/15 j/h)(1 h) = 8/15 job done that leaves (15-8)/15 = 7/15 to do (1/5)job/hr * t = 7/15 job t = 35/15 hr for S to finish 35/15 hr * 60 min/hr = 140 min

**algebra**

3j(j^2-17j +70) =3j (j-10)(j-7)

**algebra**

9 r^2 - 30 r + 25 = 0 (3 r -5)(3r-5) = 0 r = 5/3 and 5/3 repeated, parabola just touches r axis

**algebra**

2(2a^2-5a+3) is 2(2a-3)(a-1)

**algebra**

64 z^2 - 1 That is the difference of two squares remember a^2-b^2 = (a-b)(a+b) so (8z-1)(8z+1)

**nobody knows**

Did you try to copy and paste? That does not work.

**physics**

Assuming that they are in series, 1.2 amps goes through each so current density = 1.2 /(pi d^2/4) for each

**calculus too hard**

Use Steve's solution if no typos in problem statement.

**calculus too hard**

I am still not sure it is right maybe dx/dt = k(a-t) ?? if so try x = c + p t - kt^2/2 then dx/dt = p -kt then p = ka and if c = 0 then dx/dt = 0 +ka -kt = k(a-t) so then x = ka t - k t^2/2

**typos?**

I think you might mean dx/dt = k(a-x) but what is c?

**Maths**

tan 60 = X1/1 tan 30 = X2/1 d = X2 - X1 v = d/t t in hours = 10 s /(3600 s/hour)

**math**

angles OBA and OCA are right angle BOC is 90-40 = 50 ABC =180 - 20 - 90 = 70 = ACB

**Maths**

1.12 p = 15,000

**Calculus 3**

No, because multiply by sqrt 14 which is |n|

**Calculus 3**

n = 3 i +2 j + k we want F dot n = |F| |n| cos angle but we are given that |F| cos angle is 3 z/sqrt14 so what is |n|? sqrt (9+4+1) = sqrt 14 ha, that helps :) so F dot n = 3 z so do the integral of 3 z over the surface

**Calculus 3**

http://tutorial.math.lamar.edu/Classes/CalcIII/SurfIntVectorField.aspx boundary in first quadrant means x from 0 to 2 and y from 0 to 3 (sketch that thing)

**math**

89/18 =4 + something 4 * 18 = 72 89 -72 = 17 left over

**Physics**

well, sure the tension does work, but the idea is that you do not have to get into the innards of this system because its kinetic energy is described by the (1/2)(m1+m1)v^2 and (1/2) I omega^2 and its potential energy by the m g h of the two objects. You could solve the whole ...

**sorry, read -1 not -3**

-3(-2) = +6

**MATH**

y = -1 x +42 slope = -1 = change in y/change in x if change in x - -1 then change in y /-2 = -1 so change in y = -1 (-2) = +2

**Physics**

max ke = max Pe = m g h h = r (1-cos 60) = r/2 so max (1/2) m v^2 = m g r/2 max v^2 = g r T = m g + m v^2/r T = m (g + g) = 2 m g = 2(.05)(10) T = 1 Newton

**physics**

4 *10 = 40*v v = 1

**Physics**

q = c v same q on each v1+v2 = 100 q/c1 +q/c2 = 100 q/4 + q/2 = 100 3 q/4 = 100 q =400/3 on each now same v on each and total charge=800/3 and total c = 6 v = q/c = 800/18 = 44.4 volts

**algebra**

let's see we need 5*5-1 in the middle something of form (5c ) ( 5) (5c-1) (c +5)NO that gives +24, we want - (5c+1)(c-5) = 5c^2 -24c -5 progress so (5c+d)(c-5d) = 5c^2 -24cd -5d^2 done

**physics**

Ac = g there = v^2/R = omega^2 R omega = 2 pi radians/24 hours =2 pi radians /(24*3600)seconds R is given so find omega^2 R

**Specialist Mathematics**

|x+y| two possibilities A: x+y B: -x-y = -(x+y) if A: x+y is maximum when both are + then x+y = |x|+|y| if B: -(x+y) has same absolute value as A etc

**History -**

I think I might have picked C because some of them are in South America and Asia and the Middle East.

**Linear Relations MATHS**

You are welcome

**Linear Relations MATHS**

That means 3/4 of the way along the line segment from A to B That means 3/4 in x and 3/4 in y in x -4 +(3/4)(6 - -4) = -4+ 3*10/4 = = -16/4 +30/4 = 14/4 = 3 1/2 in y 6 + (3/4)(-7-6) = 6- 13*3/4 = 24/4-39/4 = -15/4 = -3 3/4 so (3.5 , -3.75) In part B same deal but times 3, not ...

**Math**

36 = .6 p so p =36/.6 = 360/6 = 60

**math help**

does "cross product" or "vector product" ring a bell? the cross product of two vectors is perpendicular to both +i +j +k +2 +1 +1 +1 -1 +2 (2+1)i +(1-4)j + (-2-1)k = 3i -3j -3 k

**History - Help**

http://www.fsmitha.com/h2/ch14-4.htm

**History - Help**

You are welcome.

**History - Help**

Yes, see https://en.wikipedia.org/wiki/Westphalian_sovereignty

**Mathematics**

50 (30/25) = 2*30 = 60

**Social Studies**

Where should I start???? Load and unload ships, trucks, trains, and planes or in the case of ports at the mouth of rivers (New Orleans, Rotterdam), transfer cargo between river barges and seagoing ships. Builds and repair ships and port facilities. Do the paper work and number...

**math**

(0,5800) and (5,7420) (7420-5800)/5 = (y-5800)/(x-0)

**math**

Well I showed you that the first choice is NOT a solution to the equation. However It might not be the only one. Check them all.

**math**

Try each of them for example -52 = -5(10) - 4 -52 = -54 I do not think so check the others as well.

**Math**

You are welcome.

**Math**

L,w,h area = 2 Lw + 2 Lh + 2wh = 600 so Lw+Lh+wh = 300 but L = 3w so 3 w^2 + 4 w h = 300 now V = L w h = 3 w^2 h so h = V/3w^2 3 w^2 + 4 w(V/3w^2) = 300 4 V/3w = 300 - 3 w^2 (4/3)V = 300 w - 3 w^3 we want d(4/3)V /dw = 0 300 = 9 w^2 w = (10/3)sqrt 3 L = 10 sqrt 3 w L = 100 so...

**physics**

I agree but wonder about the straight line. There is not enough gravity to hold them down, but there is still a force toward the earth center so I think the departure path would curve.

**Math**

You never know who will be online. All you can do is post the question. There are a lot of math teachers who check in here.

**Math**

Yep, it's right :)

**calculus**

right triangle 3,4,5 or 60,80,100 x= 60 y = 80 z = hypotenuse = 100 dx/dt = 80 dy/dt = 100 z^2 = x^2+y^2 2 z dz = 2 x dx + 2 y dy z dz/dt = xdx/dt +y dy/dt 100 dz/dt =60*80+80*100 dz/dt = 6*8+80 dz/dt = 128 km/hr

**History**

Heavens! Look at a map. What is the biggest river in the now United States? Texas where the beef comes from for Richmond is west of the river. Remember that fleet coming up from the Gulf of Mexico ("Damn the torpedoes" :)

**another no way**

You try first. I already took the course.

**No way**

I do not see any attempt by you to do these problems. I already took this subject and do not need the practice. You try first. Also read what you typed.

**Math**

25-13 = 12 which is the sum of the two bases at the ends h is the height area of rectangle in the middle = 13 h x is base of one triangle (below the 10) so 12-x is the other(below the 15 (12-x)^2 + h^2 = 225 x^2+h^2 = 100 ---------------------subtract 144-24x = 125 x = 19/24 ...

**math**

(9/14)(35,000) =

**Math**

Yes but do the division 9/3 = 3 laps/min 30/6 = 5 laps/min 20/5 = 4 laps/min Mary does the most laps /min

**math**

s = 3d d + 3d = 116 4 d = 116 d = 29 so s = 87

**Math (please help!!)**

It is also the incenter B http://www.google.com/search?q=incenter+of+triangle&ie=utf-8&oe=utf-8 and point of concurrency C http://www.google.com/search?q=iconcurrency+of+perpendicular+bisectors&ie=utf-8&oe=utf-8 and D

**30 to what ?**

30deg to horizontal or vertical? In either case, use Snell's law.

**math**

5 per year 5*20 = 100 twenty years

**history**

Clove production, slaves See: www.blackpast.org › Geography: Global African › Africa › KenyaSeyyid Said, also known as Said ibn Sultan, was a resourceful and energetic sultan ... moved the capital from Arabia to Zanzibar in order to initiate clove production...

**Social Studies**

push --> potato famine and nasty bosses drive people out pull ---> jobs and land draw those people as immigrants to Ellis Island.

**calcululs help me**

4x^2+8xy+9y^2-8x-24y+4=0 8xdx+8xdy+8ydx+18ydy-8dx-24dy=0 (8x+18y-24)dy= -(8x+8y-8)dx dy/dx = (-4x-4y+4)/(4x+9y-12)agree numerator = 0 when x+y=1 yes find d/dx(dy/dx)of (-4x-4y+4)/(4x+9y-12) = [(4x+9y-12)(-4dx-4dy)-(-4x-4y+4)(4dx+9dy)]/dx[(4x+9y-12)]^2 =4[(4x+9y-12)(-dx-dy)+(+...

**chemistry**

ZnO + 2HCl ---> ZnCl2 + H2O By the way H2O is ...... Zn = 65 g/mol O = 16 g/mol H = 1 g/mol Cl =35.5 g/mol 13.64 g ZnCl2 * 1 mol/(65+71)g = mols of ZnCl2 now you should be able to continue.

**American History**

I think A) http://millercenter.org/president/biography/monroe-foreign-affairs

**error !**

I multiplied by distance not time average speed = v/2 distance = .25 = t (v/2) t = .5/v then 3 v = 20 *.5/v 3 v^2 =10 v^2 = 10/3 v = sqrt(10/3) ================== check 3 v = 20 * t 3 sqrt (10/3)= 20 * .5/sqrt(10/3) 3 (10/3) = 20 * .5 yes

**physics**

change in momentum = force * time 3 v = 20*.25