Friday
August 29, 2014

Posts by Damon


Total # Posts: 18,148

math
sketch it in quadrant 2 y = 1 x = -1 tan theta = y/x = -1
May 19, 2014

geometry
1 meter by 0.2 meter boards? area board = .2 m^2 area floor = 50 m^2 50/.2 = 500/2 = 250
May 19, 2014

Math
when does 4 x = 2 pi , a full circle ? x = 2 pi/4 = pi/2 the single amplitude is given, 3
May 19, 2014

Algebra
d^2 = (y2-y1)^2 + (x2-x1)^2 d^2 = 5^2 + 12^2 = 13^2 (5 12 13 right triangle) 13
May 19, 2014

math help
x = -7717/335 y = -36738/335 z= 16662/335
May 19, 2014

typo?
-3 ??? x ???? +13y+29z=81 and what do you want? A solution using Gauss Jordan ? If so go to: http://www.gregthatcher.com/Mathematics/GaussJordan.aspx
May 19, 2014

algebra 1
multiply both sides by -1 This changes the direction of the arrow 2 x/7 + 8 < 9 2 x/7 < 1 2 x < 7 x < 3.5
May 19, 2014

math help
Just told you, 4/5
May 19, 2014

math help
sin R = 3/5 = r/s t^2 = 5^2 - 3^2 = 25 - 9 = 16 so t = 4 tan T = t/s = 4/5
May 19, 2014

Algebra 2
ten scores in order: 81 81 82 84 85 86 89 93 94 95 sum = 870 mean = 870/10 = 87 median 85.5 (5 above, 5 under) mode = 81 (there are two of them)
May 19, 2014

algebra1
LOL - Yes, I suppose.
May 19, 2014

algebra1
******** -6 x^2 + 4 x + 3 ********____________________________ (3x+2) | -18 x^3 + 0 x^2 + 17 x + 6 *********-18 x^3 -12 x^2 *****************12 x^2 + 17 x + 6 *****************12 x^2 + 8 x *************************9 x + 6 *************************9 x + 6 remainder = 0...
May 19, 2014

Algebra 2
area bulls eye = pi (6^2) total area = pi (16)^2 6^2/16^2 = 2^2*3^2 /2^8 = 9/2^6 = 9/64 = .140625
May 19, 2014

Algebra/can you explain how this is set up
150 * 150 * 150 ------ P1 times or log x = P1 log 150 using for example ten base then x = 10^log x
May 19, 2014

Math help
1, 2, 3, 4, 5, 6 p greater than 2 = 4/6 = 2/3 p 2 or smaller and prime = 2/6 = 1/3 2/3 + 1/3 = 1 every single side of the cube is either greater than 2 or prime (two and one) so you simply will get the desired result in 100% of your rolls :)
May 19, 2014

Algebra
combinations of 10 three at a time = 10!/ [ 3! (10-3)! ] = 10 * 9 * 8 *7* .......1 /[3*2(7*....1) ] = 10 * 3 * 4 = 120 or look up binary coefficient (10,3) = 120 or look at Pascal's triangle row 10, element 3 (the eleventh row, fourth element really since zero counts) ...
May 19, 2014

Science
Note from wikioedia: Uranium-238 - Wikipedia, the free encyclopedia en.wikipedia.org/wiki/Uranium-238 Wikipedia Jump to Radioactivity and decay - [edit]. 238U radiates alpha-particles and decays **** (by way of thorium-234 ****** and protactinium-234) into uranium-234. 234U ...
May 19, 2014

Science
U238 for example has 92 protons and therefore 146 neutrons It loses an alpha particle which is a helium nucleus, 2 protons and 2 neutrons so NOW we have an element with 92 - 2 = 90 protons 238 - 4 = 234 atomic mass ignoring E = mc^2 What has 90 protons? Th Thorium 232 is usual...
May 19, 2014

math
33/77 , 21/77 , 7/11 Now which is big and which is small ?
May 19, 2014

Social Studies
Gee, remarkable. You are welcome :)
May 19, 2014

Social Studies
1 yes 2 yes 3 yes !!! 4 yes 5 I think d because of shape of Mexico city valley between mountains 6 yes 7 yes 8 yes 9 yes
May 19, 2014

Algebra 2
I still do not have any idea what the question is.
May 19, 2014

Algebra 2
| 3 2 5 | |B11 B12 B13| |5| | 2 -1 8|+|B21 B22 B23|=|0| | 4 7 -3| |B31 B32 B33| |3| Is that what you mean ??? or what ?
May 19, 2014

Algebra 2
Are they matrices? is A square and C a column?
May 19, 2014

Algebra 2
Sorry, I don't get it. Is A a square matrix and B and C columns or what? do you mean A * B or A + B ???
May 19, 2014

Algebra 2
|+3 +2 -5 | |x| |20| |+5 -10 8 |*|y|=|17| |-8 +11 -2| |z| |29| to solve: http://www.gregthatcher.com/Mathematics/GaussJordan.aspx
May 19, 2014

CHEMISTRY
22.4 liters/mole for perfect gas at STP C + O2 --> CO2 46 g of C which is 12 grams/mole so we need 46/12 = 3.83 moles of carbon and 3.83 moles of O2 3.83 * 22.4 = 86 liters
May 19, 2014

Math Help? Check my answers.
4. Write the expression using a single exponent. 2^2 • 2^8 Oh my ! a^x * a^y = a^(x+y) !!!!! 2^2 * 2^8 = 2^(2+8) which is 2^10
May 19, 2014

Math Help? Check my answers.
3. ***** -7x***** - 5x^2 + 5, what is the coefficient of x -7x so -7 is coef of x !!!
May 19, 2014

Math Help? Check my answers.
2. 6x^4 + 3x^3 - 2x^2 + 15x - 14 one ,,, two,,,three,,four, five
May 19, 2014

Math Help? Check my answers.
2. disagree 3. disagree 4. disagree 5. disagree sort of. A works but 10*10^7 is usually written 1 * 10^8 which is C
May 19, 2014

Algebra 2
For heavens sake look up the definition of these terms instead of guessing !!!
May 19, 2014

Physics
b) w = 2 pi/T = sqrt (k/m) (2 pi)^2 /T^2 = k/m k = 2 (2 pi)^2/ 1.8^2 = 24.4 n/m (I do not know how you got the same answer) !!!! c) when it is stopped at x = .08 meters, all the energy is potential (1/2) k x^2 (1/2)(24.4) (.08)^2 = .0781 Joules d) Ke = .0781 Joules = (1/2)mv^2...
May 19, 2014

algebra/have no idea how to do this one
That is what I did Mary Ann I use r = interest rate/number of payments in a year so your n t is my n and your r/n is my r and my n is 40 *12, your n t
May 18, 2014

algebra/have no idea how to do this one
are we doing amount of an annuity here? here? If so: A = payment [ (1+r)^n -1 ]/r r is interest PER PERIOD = .08/12 = .006667 n is number of periods = 40*12 = 480 months payment = 150 A = 150 [1.006667^480 -1 ] / .006667 A = 150(23.27339)/.006667 A = $ 523,624.99
May 18, 2014

math
Try tessellating a circle.
May 18, 2014

Calculus
Ah hah, a real calculus problem :) dV/dt = - k V dV/V = -k dt ln V = -k t + C e^ln V = V = e^(-kt+C) = c e^-kt so here at t = 0 e^0 = 1 so V = c = 70,000 and V = 70,000 e^-kt now when t = 10/12 years, V = 22,222 22,222 = 70,000 e^-k(.83333) ln (22,222/70,000) = - .83333 k -1....
May 18, 2014

Calc
total lift if you release water to the atmosphere .5 meter up at the pump = .5 + .75 meters = 1.25 meters total mass = 1000kg/m^3 * 50*25*1.5 = 1.875 *10^6 kg total weight = m g = 9.81*1.875*10^6 = 1.84*10^7 Newtons total work done = weight * distance = 1.84*10^7 *1.25 = 2.23...
May 18, 2014

Calc
The same. You have to lift the center of mass of the water up to the pump either way. Of course if you attach a tight hose to the outlet you save lifting a half meter by releasing the water at ground level rather than .5 meter up.
May 18, 2014

Calculus
See the reply to the question above this one from "Jen". Find the mass and m*g, the center of mass, and how far you lift the center of mass. In all these questions if you lower the outlet with a tight outlet hose you can siphon the water out without doing any work at...
May 18, 2014

Calculus
In your earlier question you did not "factor out" the log function. you (or Reiny) said if log x = log y then x = y
May 18, 2014

Calculus
Not calculus. algebra .08/4 = .02 per quarter n = number of quarter years 15825 = 4500 (1.02)^n log (15825/4500) = n log 1.02 .546131 = n log 1.02 n = 63.5 quarter years so 63.5 /4 = 15.88
May 18, 2014

Need help with pre cal hw
LOL, physicist / mathematician again.
May 18, 2014

Need help with pre cal hw
note 160 = south - 20 North distance = 8 cos 30 - 6 cos 20 East distance = 8 sin 20 + 6 sin 20 distance = sqrt (North^2 + east^2) 2. call it 132 = south - 48 north distance=-61.1cos 48 +76.5sin 36.5 east distance =61.1sin48 +76.5cos 36.5 tan theta = north/east
May 18, 2014

Physics
How far does it go in 30 seconds (1/2 minute)? (1/2)min * 1 hr/60 min *120,000 m/hr = 1000 meters 360/20 = 18 the circumference of the turn = 18,000 meters 2 pi r = 18,000 r = 2865 meters Ac = v^2/r = (120,000/3600)^2 / 2865 = .388 m/s Check my arithmetic !! usually plane ...
May 18, 2014

HELP PLEASE !!
b a
May 18, 2014

algebra/I appreciate your help
.055/4 = .01375 per quarter 3 * 4 = 12 quarters 625 * 1.01375^12 = 736.29
May 18, 2014

Calculus
You are NOT factoring it out You are saying that if log x = log y then x = y
May 18, 2014

Physics
Max force at bottom = 20 = m v^2/r + m g 20/.25 = v^2/1.2 + 9.81 v^2 = 70.19 *1.2 = 84.2 v = 9.17 m/s
May 18, 2014

Physics
ax = 5 m/s^2 ay = 8 m/s^2 vx = Vi + ax t = 5 + 5 t vy = 0 + ay t = 8 t x = Xi + Vi t +(1/2) ax t^2 x = 0 + 5 t + (1/2)5 t^2 y = 0 + 0 t + (1/2)8 t^2 at t = 2 x = 0 + 10 +2.5(4) = 20 y = 0 + 0 + 4 (4) = 16
May 16, 2014

Algebra 1
when x = 0, undefined (very big to the right, very negative to the left of origin) when x = 1, y = 2 when x = -1, y = -2 when x = 2, y = 1 when x = -2, y = -1 when x = 5218575, y is very close to x axis above it when x = -5218575, y is very close to the x axis under it.
May 16, 2014

Physics
You are welcome.
May 16, 2014

Physics
Maybe in c you mean what is the velocity angle to the x direction at t = 1 ??? dx/dt = 4 dy/dt = 3-2 = 1 tan^-1 (1/4) = 14.03 degrees
May 16, 2014

error - sorry
|V| = sqrt (16+4) = 4.47 m/s theta = tan^-1 -2/4 = -26.6 degrees
May 16, 2014

Physics
dx/dt = 4 dy/dt = 3 t -2 so at t = 0 V = 4 i - 2 j |V| = sqrt (16+9) = 5 m/s theta = tan^-1 -2/4 = -26.6 degrees b) Ax = 0 Ay = 3 m/s^2 c) is a typo I think.
May 16, 2014

physics
angular velocity constant = omega = 2 pi radians/3600 seconds tip speed is also constant = omega * r
May 16, 2014

physics
d is diameter of circle :) C = pi d t = pi d/v
May 16, 2014

physics
v = sqrt (2 g h) u = 14.4 so |V|= sqrt(u^2+v^2) = sqrt (2 g h + 14.4^2)
May 16, 2014

physic
twice
May 16, 2014

pre algebra
SKETCH A GRAPH !! Always note symmetric about x = 0 note hits bottom at (0,-20) (so that is the vertex) so (y +20) = a x^2 at (10,80) 100 = a(100) a = 1 so I claim x^2 = y + 20
May 15, 2014

algebra
(m-1) or (1-m) 7 - m + 1 = 3 or 7 -1 + m = 3 m = 5 or m = -3 check if m = 5 |m-1| = 4 4 = 4 good if m = -3 |m-1| = 4 good
May 15, 2014

Math - Int Trig
for every a+bi there is a a-bi solution (x-2i)(x+2i)(x-3i)(x+3i) = 0 (x^2 +4)(x^2+9) = 0 x^4 + 13 x^2 + 36 = 0 ================= (x-i)(x+i)(x+10) = 0 etc
May 15, 2014

Precalculus
2 x^2 + 4 x = y^2 - 4 y +4 2 x^2 + 4 x = (y-2)^2 x^2 + 2 x - (1/2) (y-2)^2 = 0 x^2 + 2 x + 1 - (1/2) (y-2)^2 = 1 (x+1)^2 - (y-2)^2/(sqrt 2)^2 = 1 Hyperbola, you look up the stuff for it.
May 15, 2014

math
when x = 0, y = 3 so make a point (0,3) when y = 0, x = -1 so make a point (-1,0) the line goes through those two points and off into the distance left and right
May 12, 2014

Science
sorry, typo 1.5 * 63 Joules
May 12, 2014

Science
4.5 * 63 Joules
May 12, 2014

Algebra 1 Answer Evaluation
Yes, the only solutions to the first problem are the imaginary numbers +/- i sqrt 7 where i is the sqrt of NEGATVE one
May 12, 2014

Algebra 1 Answer Evaluation
x^2 + 0 x + 7 = 0 x = [ 0 +/- sqrt(-28) ]/2 x = +/- 2 sqrt -7/2 x = +/- sqrt(-7) or +/- i sqrt 7 ================================= x^2 - 0 x -16 = 0 x = [ 0 + /- sqrt (0 +4*16) ]/2 x = +/- 2*4/2 x = +/- 4 what else is new :)
May 12, 2014

math
position = speed * time + initial position or d = s t + di 90 = s (2) + di 135 = s(3) +di subtract 45 = 3 s - 2 s = s and 135 = 45(3) + di or di = 0 so in the end d = 45 t check that for example does 270 = 45(6) ???
May 12, 2014

math
-4 = (1/4) (0) + b b = -4 y = (1/4) x -4 or 4 y = x - 16 graph that line
May 12, 2014

math
(-2 - 2) / (4-6) -4 / -2 2
May 12, 2014

trig
sin 15 = 135/ hypotenuse tan 15 = 135/d along ground
May 12, 2014

Calculus answer check
s = .7 t^2 ds/dt = v = 1.4 t 4 = 1.4 t t = 4/1.4 = 2.86 seconds It asked for t given v = 4 m/s
May 9, 2014

maths
(p-7)(p+6)
May 6, 2014

Pre - Cal
start at the middle up 4 end up 20 (16 above middle y = kx^2 16 = k(40)^2 16 = k (4)^2(10^2) 1 = 100 k k = .01 so , adding the 4 at the middle y = 4 + .01 x^2 at x = 20 y = 4 + .01 (4)(100) = 8
May 5, 2014

Pre - Cal
(x+3)^2 = a(y-1) (4+3)^2 = a (-5-1) 49 = -6 a a = -49/6 x^2 + 6 x + 9 = -49/6 (y-1) x^2 + 6 x + 54/6 = - 49 y/6 + 49/6 x^2 + 6 x - 5/6 = -49 y/6 6 x^2 + 36 - 5 = -49 y
May 5, 2014

Pre - Cal
4y^2+4y-16x=0 y^2 + y = 4 x y^2 + y + 1/4 = 4 (x + 1/16) (y+1/2)^2 = 4 (x+16) vertex at (-16 , -1/2)
May 5, 2014

Calculus
integral f(t) dt from 5 to 7 sin 7 - sin 5 = .657 - .959 = -.30 if angle is in radians or .121 - .087 = .0347 if angle is in degrees I suspect you left a pi out or something.
May 5, 2014

English
d cautionary is correct
May 5, 2014

Help math only 1 question easy!
3 * 2 * 1 = 6
May 5, 2014

physics
distance = speed * time wavelength = speed * period = speed / frequency = 3 * 10^8 m/s / 76 = 3.95 * 10^6 meters = 3950 km Either you have a typo or you are talking about a super low frequency system that is used to communicate with submarines underwater. It is 360 degrees ...
May 5, 2014

Physics
7 m/s * 3600 s/hr /1000 m/km = 25.2 km/hr which is about 15 miles/hour 10m/s = 36 km/hr which is about 22 miles/hour If you are really, really fast you might run 100 meters in around 10 seconds :) I am sure you can think of something :)
May 5, 2014

Algebra
-10 (x^3 - 3 x + 2) /[-5(x-1)] 2 (x^3 - 3 x + 2) / (x-1) 2 (x^2+x-2)(x-1)/(x-1) 2 x^2 + 2 x -4
May 5, 2014

pre calculus
Vx = 1200 cos 6 Vy = 1200 sin 6 |V| = sqrt (Vx^2 + Vy^2)
May 5, 2014

maths
18 - 24 j 9 - 8 j
May 5, 2014

maths
That is not an equation.
May 5, 2014

maths
[(x+a)(x+b)] / [(x+a)(x+a)] = (x+b)/(x+a)
May 5, 2014

math?
82 - 5(15) = 82 - 75 = 7
May 5, 2014

AP Physics B
4.2 * heat of fusion of water 4.2 * 79.5 kcal/kg = 334 kCal
May 5, 2014

maths
I have no idea. You did not say how much he spent total.
May 5, 2014

physics
The net horizontal force is 35 -2.9 = 32.1 N
May 2, 2014

Calculus
if dP/dx = x e^-x^2 then p = -(1/2)e^-x^2 + C 15,000 = -.5 /e + C agree so C = 15,000 + .1839 = 15,000.1839 so p = -(1/2)e^-x^2 + 15,000.18
May 2, 2014

Physics/Calculus
f = -k x 21714 = k (3) W = (1/2) k x^2 do for x = 1/2 inch then for 1 inch and subtract the half inch result
May 2, 2014

Calculus
work = integral w dz w = 4.5 (180-z) so work = integral from z = 0 to z = 180 of 4.5 (180-z)dz = 4.5*180 (180) - 4.5 (1/2)(180)^2 = (1/2)(4.5)(180)(180) or half the weight over the whole distance of course :)
May 2, 2014

Physics
half the weight times the distance
May 2, 2014

Physics
twice as far (1/2) k x^2 where k = force/distance
May 2, 2014

Math
2*8 + 2*w = 30
May 2, 2014

Calculus Help and Check
I gave you my answer which is quite different.
May 1, 2014

calculus help
delta x = pi/8 x at pi/16 , 3pi/16, 5pi/16, 7pi/16 so 2 cos^3 pi/16 = 1.887 2 cos^3 3 pi/16 = 1.1497 etc add them up and multiply by pi/8
May 1, 2014

calculus help
Well, I gave you my answer which is quite different.
May 1, 2014

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