Saturday
November 29, 2014

Posts by Damon


Total # Posts: 19,622

Physics
PLEASE CHECK FOR TYPOS slope of the air slope of air WHAT?
November 4, 2014

least to greatest fractions
6/9 is 2/3 if that is what you are asking. I have no idea what the second and third lines are about 4/40 is 1/10 2/5 is 4/10 maybe 7/10 is next ? 3/7 is 6/14 8/14 is 8/14 5/7 is 10/14 so next would be 12/14 = 6/7
November 3, 2014

math
y = 5 x + 100 your brother has the sign of the slope wrong
November 3, 2014

Algebra
q = [ (x+113)/2 ]^1/3 q = [ (137+113)/2 ]^1/3 q = 125^1/3 = 5
November 3, 2014

Math
-1.4 b = -28 b = 28/1.4 = 20
November 3, 2014

Algebra
y = x^5 - 1/3 inverse x = y^5 - 1/3 y^5 = x + 1/3 = -31/96 + 32/96 = 1/96 if y^5 = 1/96 then y =1/2.5 = .401
November 3, 2014

Calculus
cost of x tables = [160-.5(x-250)]x for x>/=250 c = 160 x + 125 x - .5 x^2 c = 285 x - .5 x^2 dc/dx = 285 - x max when x = 285 then c = .5*285^2 = 40,612.50 and c = 0 when x = 0 of course but also when x = 285*2 = 570
November 3, 2014

Algebra
f^-1(1) = 2 (when y = 1, x = 2) f^-1(2) = 5 f^-1(5) = 3
November 3, 2014

Physics
F = m a 12.1 = 5.9 a solve for a d = (1/2) a t^2 2.6 = (1/2) a t^2 we know a, solve for t v = a t
November 3, 2014

Algebra
x = 3 y^3 + 2 y^3 = (x-2)/3 so y = [ (x-2)/3 ]^(1/3) = f-1(x) so [ (x-2)/3 ]^(1/3) = 4 [ (x-2)/3 ] = 64 x - 2 = 192 x = 194
November 3, 2014

algebra
4 q = 5 * 18 2 q = 5 * 9 q = 45/2 = 22 1/2
November 3, 2014

Algebra
1,1 6,7 2,7 2,3 7,9 3,9 3,5 3,1 8,7 4,7 4,3 9,6 5,6 1,6 1,2 6,8 2,8 2,4 7,10 3,10 3,6 3,2 this thing is a pretty good vacuum cleaner, keep going until it repeats a point :)
November 3, 2014

Algebra
if y = x^2 - 2 x f(y) = (x^2-2x)^2 - 2(x^2-2x) = f(f(x)) so x^2-2x = (x^2-2x)^2 - 2(x^2-2x) of course x = zero will do :) let z = x^2 - 2x z = z^2 - 2 z z^2 - 3 z = 0 z (z-3) = 0 so another solution is x^2-2x = 0 = x (x-2 we already have x = 0 so now also have x = 2 and also ...
November 3, 2014

Algebra
I would have said something like that but have been having fun :) She has an imaginative teacher!
November 3, 2014

Algebra
y = (3x-7) / (x+1) inverse x = (3y-7) / (y+1) x y + x = 3 y - 7 3 y - x y = x + 7 y (3 - x) = (x+7) y = -(x+7)/(x-3) f^-1(x) = -(x+7)/(x-3)
November 3, 2014

physics
What you did makes sense to me. I guess we are assuming that the sphere has a very thin wall thickness to get the (2/3) m r^2
November 3, 2014

Math
(5/6 )24 = 20 pennies 20 / 50 = 2/5
November 3, 2014

Math
(2/5 )35 = 14 did not go in piggy bank (1/2) 14 = 7
November 3, 2014

trig actually, or maybe vector trig
4.19 cos 10.4
November 3, 2014

PHYSICS
lol - the other half of the problem 4.19 sin 10.4
November 3, 2014

Physics
emf = N d flux /dt emf = 660 B pi r^2 d/dt (sin 2 pi t/T) when t = .024, t/T = 1/8 T = .192 second so emf = -660 (pi r^2) (2 pi/T)B cos (2 pi t/T) now I do not know what "average means. Obviously the average of a cosine function is zero. You might guess they mean ...
November 3, 2014

Physics 11U
goes up from 2 to 8 or 6 meters do vertical problem v = Vi - g t 0 = Vi - 9.8 t at the top (8meters) so t at top = Vi/9.8 h = 2 + Vi t - 4.9 t^2 at top 8 = 2 + Vi t -(1/2)(9.8) t^2 6 = Vi t -(1/2)(9.8) t^2 6 = Vi^2/9.8 - (1/2) Vi^2/9.8 12 (9.8) = Vi^2 Vi = 10.84 m/s now do the...
November 3, 2014

Math Help!
well, 30 would be 900 and 28 would be 784 so do my proportion thing again 28 x 30 784 872 900 (872 -784)/ (x-28) = (900-784)/(30-28) x-28 = 2*88/116 x = 28 + about 1.5 or around 29.5 so 30 try calculator sqrt (872) = 29.529
November 3, 2014

math
speed = distance/time speed1 = 1020/3.30 speed2 = 1020/2.75 so speed2/speed1 = 1020/2.75 / 1020/3.30 = 3.30/2.75
November 3, 2014

Math Help!
go back and see how I did the earlier one with linear interpolation. It clearly works best when you pick perfect squares above and below the desired answer.
November 3, 2014

Physics
find induced EMF from 193 *area * dB/dt E = (193)pi (5.5*10^-2)^2 (.908) current = i = E/.241 now find B due to i B = mu N i/2 r = 4 pi*10^-7 (193)(i)/(2*5.5*10^-2)
November 3, 2014

Math Help!
15 --> 225 14 --> 196 13 --> 169 12 --> 144
November 3, 2014

Math Help!
x 3 z 4 y 9 14 16 linear interpolate (z - 3)/(14-9) = (4-3)/16-9) z - 3 = (5)(1)/7 z = 3 + 5/7 or a bit over 3.5 so pick 3.7 now use calculator 3.742 :)
November 3, 2014

Physics
(1/2) m v^2 = 182 m v = 27.6 so m = 27.6/v (1/2) (27.6/v) v^2 = 182 (1/2) (27.6) v = 182 etc
November 3, 2014

Help!-algebra
agree, c
November 3, 2014

Math Help!
In other words, Brady is right :)
November 3, 2014

Math Help!
0.8743 8743 8743 8743 * 10^-4 + 8743 * 10^-8 + 8743 * 10^-12 ...... repeating decimal, infinite geometric series a = 8743 r = 10^-4 sum = a/(1-r) = 8743 /(1 - .0001) =8743/.9999 = 87430000 / 9999 which is a rational number being the quotient of two integers/
November 3, 2014

Physics
initial mass = 73.5 + .21 initial momentum = (73.5 + .21)(2.97) final momentum is the same = .21 (29.3) + 73.5 v solve for v solve the second part the same way initial momentum = .21*29.3 = (.21+61.5)v
November 3, 2014

physics
calculate moment of inertia I alpha = change in angular rate/change in time = (34-0)/18 radians/second^2 Theta = (1/2) alpha t^2 Ke = (1/2) I w^2 tangent acceleration at rim = r * alpha radial acceleration = v^2/r = w^2 r where w = (1/2) 34 w (r/2) d = average speed * time but...
November 3, 2014

physics
actually Ke = (1/2) I w^2
November 3, 2014

Math
share as many sides as possible. Make it square :)
November 1, 2014

Physics
By the way, your formula is for the volume of a cylinder, not a sphere. Use (4/3)pi r^3
November 1, 2014

Physics
Volume of Glass = (4/3) pi (Ro^3 - Ri^3) mass of glass = rho V so 1.71 = 2660 (4/3) pi (Ro^3-Ri^3) so (Ro^3 - Ri^3) = 4.8214*10^-4 Now Archimedes assume rho water = 1000 1000 (4/3)pi Ro^3 = 1.71 solve for Ro^3 go back and get Ri^3 take cube roots :)
November 1, 2014

Statistics
and here is a calculator for it: http://www.neoprogrammics.com/linear_least_squares_regression/
November 1, 2014

Statistics
for example: http://mathworld.wolfram.com/LeastSquaresFitting.html
November 1, 2014

Statistics
I do not have your data. However if you have a bunch of points (x1,y1) , (x2, y2) .... (xn,yn) then you can fit a line of form y = m x + b that "best" fits those points, the criterion being that the sum of the squares of distances from the points to the line is ...
November 1, 2014

AP Calc. AB
y = 2 x + sin x if there were an inverse it would be x = 2 y + sin y 1 = 2 dy/dx - cos x dy/dx 1 = dy/dx (2-cos x) dy/dx = 1/(2-cos x) at x = 2 dy/dx = 1/(2-cos 2) = 1/(2 +.416) = .41
November 1, 2014

AP Calc. AB
because it does not pass the vertical line test. for every value of g there are multiple values of x because sin x is the same for many x values.
November 1, 2014

College Chemistry
370g/[(55.85 x 2) + (13 x 3)] = 2.32 mol Don't you mean 16 * 3 not 13 * 3 ?
November 1, 2014

calculus
Hey I did a couple. Now you do some.
October 31, 2014

calculus
at 1, y = 2 at 3, y = 0 dy/dx = -2x + 3 = 0 if x = 3/2 at x = 3/2, y = 2.25 so max at x = 3/2 and min at x = 3
October 31, 2014

calculus
df(x)/dx = 3 x^2 that is the slope at x = 3 slope = 3*9 = 27 so y = 27 x + b put in point at x = 3 to find b 27 =27 * 3 + b so -54 = b so y = 27 x - 54 at x = 2.7 y = 27 * 2.7 -54 = 18.9 the real answer would be y = 19.7
October 31, 2014

statistics
http://davidmlane.com/hyperstat/z_table.html
October 30, 2014

Geometry
yes correct m' = -1/m
October 30, 2014

Social Studies
Do you really think the former colonists would have won the war if they were a minority in the 13 colonies?
October 30, 2014

Social Studies
No, it is not a.
October 30, 2014

Social Studies
I thought I answered :) Looking at the link that Ms. Sue gave you, I think I answered correctly.
October 30, 2014

Social Studies
Oh, your answer to the Saratoga question is correct for sure.
October 30, 2014

Social Studies
I think c was true. I do not think more than half the colonists were Loyalists.
October 30, 2014

math
7 have black or brown total = 4+3+1+2 = 10 7/10 You can multiply top and bottom by 6 if you want, but no different :)
October 30, 2014

Calculus
3 * (x^10 - 1)^2 * 10 x^9 or 30 x^9 (x*10 - 1)^2
October 30, 2014

Algebra 2
20 x - 1 y = -200 25 x - 1 y = 0 D = -20 + 25 = 5 Dx = | -200 -1 | | +000 -1 | / 5 = 200/5 = 40 sign ? Dy = | 20 -200 | | 25 +000 | /5 = 5000/5 = 1000
October 29, 2014

Please help-algebra
yes
October 29, 2014

Please help-algebra
Jacqueline, please read the problem again.
October 29, 2014

Please help-algebra
no .15*number + 10 0.15 x + 10
October 29, 2014

Please help-algebra
Which do you think? 15 cents times the square feet plus a 10.00 trip fee
October 29, 2014

MATH FOR THE OFFICE
31 2/8 - 29 3/8 = 30 10/8 - 29 3/8 = 1 7/8
October 29, 2014

Math Help Please! ASAP!
no y + 5 >7 subtract 5 from both sides y > 2 The second one is right
October 29, 2014

Algebra: Answer Check
No, I do not think so, suspect typo in numerator. It should be possible to factor.
October 29, 2014

Algebra: Answer Check
-3*16 -8*5 + 2 +7 -48 -40 + 9 -88 + 9 -79
October 29, 2014

Physics
momentum east = 20*3 = 60 momentum north = 30 * 2 = 60 momentum east = 50*Ve = 60 momentum north = 50*Vn = 60 Ve = 6/5 Vn = 6/5 angle = 45 speed = (6/5) sqrt 2
October 29, 2014

physics
see the problem just above this one
October 29, 2014

Physics
F = m g sin 34 = 120 x x = (1/120)(3)(9.8) sin 34
October 29, 2014

Calculus
a) 973 + .0685 ( 81000 - 20000) b) T = .9 x c) L = 973 + .0685 (.9 x - 20000) d) 973 + .0685 (.9*90000 - 20000) same as a above
October 29, 2014

Calculus
tan T = h/60 d tan T /dt = dT/dt sec^2 T = (1/60)dh/dt dT/dt = (1/60) cos^2 T dh/dt tan T = 25/60 T = 22.6 deg so cos^2 T = .852 dT/dt = (1/60)(.852) (8) in radians !
October 29, 2014

Algebra
I got 1 -3 * 16 = -48 +5* 8 = 40 - -2 = 2 +7 = +1
October 28, 2014

math
about 3+3 = 6
October 27, 2014

Fluid Mechanics
You are welcome.
October 27, 2014

Fluid Mechanics
find the pressure at the bottom p = 1 atm + density * g * h 1 atm = about 10^5 pascals or Newtons/m^2 multiply the pressure by the area F = p A A = pi r^2 b) find the pressure halfway up the tank p = 1 atm + density * g * h/2 multiply that by the total area of the side of the ...
October 27, 2014

Physics need help
P V = n R T find n in V= 1 meter^3, then we will find molar mass later 1.51*10^5 * 1 = n *8.31 (273+0) n = 66.6 mols now a mol of CO has mass 12+16 = 28 grams = .028 Kg so we have .028 * 66 = 1.85 kg /m^3
October 27, 2014

Math Homework
x^2 + 2 x + 3 > 0 upward opening parabola (holds water) where is the vertex? complete square x^2 + 2 x = y - 3 x^2 + 2 x + 1 = y - 2 (x+1)^2 = y - 2 vertex at (-1 , 2) so y is never below y = 2 x^2 + 2 x + 3 > 2
October 27, 2014

Calculus: need clarification to where the #'s go
what is an mbox? V = (4/3) pi r^3 S = dV/dr = 4 pi r^2 dS/dr = 8 pi r so dS/dt = 8 pi r dr/dt now find dr/dt if dV/dt = 80 cm^3/s dV = S * dr = 4 pi r^2 dr so dV/dt = 4 pi r^2 dr/dt so dr/dt = ( 1/4 pi r^2 )dV/dt = (20/pi 14^2) so dS/dt = 8 pi 14 (20/14^2 pi) = 80/7 =
October 27, 2014

algebra 2
c = m d + b 1.7 = 2 m + b 3.7 = 7 m + b =================== -2 = -5 m m = 2/5 so c = (2/5) d + b 1.7 = (2/5)2 + b b = 1.7 - .8 = .9 so c = (2/5) d + 9/10 or 10 c = 4 d + 9
October 26, 2014

Math
yes yes
October 26, 2014

Algebra
The function is undefined for x = 1 (x = 1 is not in the domain but otherwise all real x) but the range is from -oo < y < +oo
October 26, 2014

calculus
f(x) = 5/x f(x+h) = 5/(x+h) [f(x+h) - f(x) ]/h = [5/x+h) -5/x]/h = 5[ x - (x+h) ] /(x^2+xh)h =5 [ -h ] /(x^2+xh)h = -5/(x^2+xh) ======================== if you want use x = 4 right now = -5/(4^2 + 4 h) let h-->0 = -5/16 ======================== I would continue though let h...
October 26, 2014

calculus
here for example: http://www.sosmath.com/calculus/diff/der00/der00.html
October 26, 2014

typo
f(x) is a function of x or is it 5/8? the slope for part b is the definition of the derivative in beginning calculus. You are not supposed to know that but google it and the result will show you how to find the limit of: [ f(x+h) - f(x) ] / h as h -->0
October 26, 2014

differential equation
dA/dt = k(M-A) - cA dA/dt = k M - kA - c A but k - c is a constant call it r dA/dt = kM- rA dA/dt +rA = k M = constant for this case of M
October 26, 2014

math/limits
(x-3) / [ (x-3)(x+3) = 1/(x+3) so when x is 3 1/6
October 25, 2014

math/limits
You mean???? [(14+y)^2 - 14^2 ] / y ???? if so [ (14+y-14)(1+y+14)] / y y (y+15)/ y y+15 as y--->0 15
October 25, 2014

College Algebra
First draw the picture, center at (0,0) and radius = 5 You see that point in Quadrant 3? It makes a triangle with the -y axis hypotenuse 5, bottom 3, 4 down y axis Now draw the tangent to the circle at that point. It will be perpendicular to the radius at that point. Since the...
October 25, 2014

Math
v^3 = 5.8^3 vsphere = (4/3) pi (5.3/2)^3 subtract
October 25, 2014

physics
G Me m /r^2
October 25, 2014

csci 120
f(t) = initial balance ( 1 + r )^t where r = yearly interest percent/100 t is time in integer years after deposit
October 25, 2014

physics
m g = 690 mg - 1000 kg/m^3 * V g = 36 1000 V g = 690 - 36 = 654 N g = 9.8 so V = 654/(1000 g) rho = m/V = 690/g / .654/g = 1055 kg/m^3 just a little heavier than water (must have expelled all air from her lungs to sink like that)
October 25, 2014

Physics
friction work done = ke lost = (1/2)m v^2 force = .7 m g = .7 * 66 * 9.8 mass = 66 a = F/m = .7 * 9.8 = 6.86 m/s^2 0 = 4.4 - 6.86 t t = .641 seconds average speed = 2.2 m/s distance = 2.2 * .641 = 1.41 meters
October 25, 2014

Calculus
and also draw a picture of the circle of radius 2 and center at (0,0) so you get an idea what is going on.
October 24, 2014

physics
(1/2) m v^2 = m g h so v1 = -sqrt(2 g h) (coming down) h = -2.87 coming down going up same deal but opposite sign for v v2 = + sqrt(2*9.8*1.12) change in momentum = m (v2-v1)
October 24, 2014

Algebra Slope Intercept Form
slope is -6/2 = -3 look at what Steve did He did it exactly the way I did your last problem!
October 23, 2014

Algebra Slope Intercept Form
see http://www.jiskha.com/display.cgi?id=1414100500 exactly the same procedure.
October 23, 2014

math
2 pints then is 4 cups that is 8 half cups
October 23, 2014

Trig/Pre-Calc...
That is interesting, a little tailwind helps but a lot hurts. also zero has an effect? why? anyway if s = 3 t = .0119 *9 - .308 *3 - .0003 t = +.1071 - .924 - .0003 t = -.8172 seconds (wow, a lot) = -.82 rounded
October 23, 2014

Math
No if x = 2 y = 20 * 2 + 10 y = 40 + 10 y = 50
October 23, 2014

Math
to graph it use any two points on the line if x = 0 , y = 10 so (0,10) is one point if x = 532, y = 20*532 + 10 = 10,650 so (532 , 10,650) is a point take ruler and draw line through those points (I would suggest using like x = 5 instead of 532)
October 23, 2014

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