# Posts by Damon

Total # Posts: 29,984

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 ...

-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

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

algebra 2
ticket price p = 231/n p-4.5 = 231/(n+3) 231/n - 4.5 = 231/(n+3) 231(n+3)-4.5(n^2+3n) = 231 n 231*3 -4.5 n^2 - 13.5n = 0 4.5 n^2 + 13.5 n - 693 = 0 n = 11 or -14 so 11 =========================== check 231/11 = 21 231/14 = 16.5 yes, diff = 4.50

Physics
In other words unless there was energy input from a explosion on impact or something, no way the big block took off at 4.0 m/s

Physics
huh? .5*5 *2.9^2+.5*10*2.1^2 = 43.1 Joules .5*5 *0.9^2 + .5*10* 4^2 = 81.1 81.1-43.1 = 38 Joules more Something exploded :)

American History
ah come on !!!!

calculus
I assume you mean x^2 - x y - y^2 = 5 2 x dx - x dy -y dx - 2 y dy = 0 (2y-x)dy = (2x-y)dx dy/dx = (2x-y)/(2y-x) slope is undefined (vertical) when 2y-x = 0 or x = 2y so x^2 - x y - y^2 = 5 4y^2 -2y^2-y^2 = 5 y = +/-sqrt 5 then x = +/- 2 sqrt 5

calculus
surface area in m^2/radius in meters is meters radians is arc, no units so meters per radian

algebra
If any one of those three factors is zero, then the product is zero so z = 0 works z-1 = 0 works so z = 1 works z+3 = 0 works so z = -3 works therefore z = 0 or 1 or -3

Algebra 1- Urgent
In your table in part B the ratio is for example 10406.04/10303.01 = 1.01 check: 10303.01/10201 = 1.01 sure enough so that is increasing by ONLY ONE percent per year

I do not believe you
I think you have a very fundamental typo. We are talking about a constant rate of inflation here I bet you mean f(x) = 0.69 (1.03)^x in other words TO THE POWER x that would be 0.69 when x = 0 years, now 0.69 * 1.03 after one year 0.69 * 1.03 *1.03 after two years 0.69 *1.03*1...

option 1 is not linear because it does not change by the same amount every year. It does not have a constant slope. option 2 increases by 100 per year, constant slope, straight line, linear ----------------------- a = A y^n 1100 =A y 1210 = Ay^2 1331 = A y^3 --------------- ...

SS, PLZ HELP ME FAST!!!!
hint: Japanese eat a lot more fish than people on the great plains eat.

Calculus!! HELP!!
1) The sides of the triangle shown increase in such a way that (dz/dt=1) and (dx/dt=(3dy/dx)) At the instant when x = 12 and y = 5, what is the value of dx/dt? ========================= You do not say but I suspect this is a 5,12,13 right triangle. If I am guessing right about...

Maths
I do not know what using rotational axis means but this is an ellipse 4(x^2-2x) +9(y^2+6y) = -4 complete squares 4(x^2-2x+1)-4+9(y^2+6y+9)-81=-4 4(x-1)^2 +9(x+3)^2 = 81 (x-1)^2/4.5^2 + (x+3)^2/3^2 = 1 ellipse

Math
area = (1/2)12*5 = 30 hypotenuse BC = 13 the area = 30 = (1/2)13*AD AD =60/13

Math
120,000/50 = 240,000/100 = 2400

Probability and distribution
16 total to start I could draw a white, then blue 6/16 * 7/15 or I could draw a blue, then white 7/16 * 6/15 add them 2(42/240) = .35

math
Try then (a^9/2)^3 = a^27/ 8

History homework question
Oh, 20th Century Leaders :) Civil Disobedience.

History homework question
Hudson River school is paintings. I do not understand the second question.

American history
well, if only about in Americas (not India, Africa etc) Spain - get gold out, make Catholics France - get fur and fish out, make Catholics. Do not send many French people, just a few missionaries and trappers. England - make trading partners that grow food and ship masts and ...

physics
v = omega r 10 = omega(2) omega = 5 radians/second Ac = v^2/r = omega^2 r = 25*2 = 50 m/s^2 F = m a = .5 *50 = 25 N (not 25.5)

is (-2x)^-3 3 root of -2x?
(-2x)^-3 = 1/(-2x)^2 = 1/[-2x(-2x)(-2x)] = 1/[(-8)(x^3)] =-1/(8 x^3)

Maths
subtract area of inside circle from area of outside circle radius inside = 28/2 = 14 radius outside = 14+3.5 = 17.5 so pi(17.5^2-14^2)

Huh
Your minister of education has two brains and they are headed for somewhere else?

Jong
Hair?

typo
x = 1 and y = 1 at t = 0 y = .5 x + b 1 = .5 + b b = .5 y = .5 x + .5

calc
y = sin t + cos^2 t - sin^2 t dy/dt = cos t -2cost sint -2 sint cost at t = 0 dy/dt = 1 x = cos t +2 sin t cos t dx/dt = -sint -2sin^2t+2 cos^2t at t = 0 dx/dt = 2 dy/dt / dx/dt = 1/2 = slope x = 1 and y = 1 at t = 0 y = 1 x + b b = 0 y = x

Math
1/(x+h) - 1/x (x - x - h)/(x^2+xh) -h/(x^2+xh) divide by h -1/(x^2+xh) let h--->0 -1/x^2 sure enough

linear programming problem
the intersection with p max is of 5x+10y=560 and 50x+20y=1600 x = 12, y=50 and p = 3220 http://www.wolframalpha.com/widget/widgetPopup.jsp?p=v&id=1e692c6f72587b2cbd3e7be018fd8960&title=Linear%20Programming%20Calculator&theme=blue

calculus!
at x+h y = 1/(3-x-h) at x y = 1/(3-x) subtract 1/(3-x-h) -1/(3-x) [(3-x) -(3-x-h)]/[(3-x-h)(3-x)] [ h]/[ x^2-6x+xh-3h+9] divide by h 1/[x^2-6x+9 +xh-3h] let h --->0 1/(x-3)^2

Math - Coordinate Geometry
3y = 2 x + 3 is y = (2/3)x + 1 slope = 2/3 so y = (2/3)x + b if parallel -4 = (2/3)6 + b b = -8 so y = (2/3)x-8 3 y = 2 x - 24

math
3078+582 = 3660 =3*1000 + 0*100 + 7*10 +8*1 +0*1000 + 5*100 + 8*10 +2*1 =3*1000 + 5*100 +15*10 +10*1 =3*1000 + 6*100 + 5*10 +10*1 =3*1000 + 6*100 + 6*10 + 0*1 = 3660

Geometry
I guess it is supposed to be a triangle? If so ac can not be longer than 11+13 = 24 and it can not be shorter than 13-11 = 2 DRAW IT !

Sociology
They mean the same thing to me. Homogeneous is opposite to diverse.

calculus
LOL, either way I do physics, I find t easier to visualize step by step.

calculus
dV/dt = 3ft^3/min(1 min/60s) = .05 ft^3/s so V = .05 * 30 = 1.5 ft^3 at 30 s V = (4/3) pi r^3 so r = 0.71 ft at 30 s dV/dr = 4 pi r^2 (the surface area of course) but dV/dt = dV/dr * dr/dt so dr/dt = dV/dt / (4 pi r^2) dr/dt = .05 /(4 pi*.71^2) = .00789 feet/second

Gauss-Jordan elimination
-3 +3 -21 +3 +2 -4 ============= http://www.idomaths.com/gauss_jordan.php ===================== 1 0 2 0 1 -5 x= 2, y = -5

HELP SCIENCE
Which do you think? What does north and south pole mean?

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