Saturday
February 13, 2016

Posts by Damon

Total # Posts: 25,219

Math
-2x+y=1 -4x+y=-1 ------------ subtract because coefficient of y is the same -2x + 4x + 0 = 1+1 = 2 2 x = 2 x = 1 then -2(1) + y = 1 y = 3 so in the end (1,3)
December 3, 2015

Pre calculus
You are welcome.
December 3, 2015

Pre calculus
the slope is: (-6 - -7) / (-8 - -5) = 1/-3 = -1/3 the slope is also (y - -7) / (x - -5) = (y+7)/(x+5) so (y+7) = (x+5)(-1/3)
December 3, 2015

Simple pre cal
There are two values of y for z = 15 !
December 3, 2015

Physics
Instead of 90 degrees to the shaft (optimal) You are at 120 which is 30 degrees off. so your force perpendicular to the shaft is F cos 30 The torque is F cos 30 * 0.39 so F cos 30 * 0.390 = 49.0
December 3, 2015

Physics
http://www.jiskha.com/display.cgi?id=1449174010
December 3, 2015

Mathematics
new length and width = 19-2x area of base = (19-2x)^2 height = x so V = x (19-2x)^2
December 3, 2015

Social Studies
Lots of things like languages and foods and religions and boat designs. Did you mean to post a list?
December 3, 2015

Easy math question
7 x = 2 y + 5 2 y = 7 x - 5 y = (7x-5)/2
December 3, 2015

math
Speedy d at 110 and d at 130 t = d/110 + d/130 = d(.01678) Cannon 2 d at 120 t = 2 d/120 = d/60 = d(.01667) Speedy's time is bigger, he lost
December 3, 2015

typo
so c = -20 I do not know why I said that, typo while copying and pasting
December 3, 2015

Algebra 2 (Math)
a x^2 + b x + c (1) a(4) + b(-2) + c = -20 (2) a(0) + b(0) + c = -4 (3) a(16) + b(4) + c = -20 -------------------------------- eqn (2) tells us that c = -4 so c = -20 (1) a(4) + b(-2) = -16 (2) a(0) + b(0) = 0 (3) a(16) + b(4) = -16 ------------------------------ (1) -8 a + 4...
December 3, 2015

Physics
This is the same as the one with the skaters, just different numbers momentum before = .255 v + .365 * 0 momentum after = .255 (-.118) + .365*.649 momentum after = momentum before, solve for v
December 3, 2015

Pre calculus
That is a straight line with slope -2, it has perfectly finite values for any real x so B
December 3, 2015

algebra
for example: http://ncalculators.com/statistics/linear-regression-calculator.htm
December 3, 2015

algebra
google linear regression to get software calculator to fit straight line to your data.
December 3, 2015

Physics
momentum is zero before so zero after. 61*.63 + m* -.86 = 0 note speeds are opposite so velocity of one or the other is negative m = 61 (.63/.86)
December 3, 2015

Math
12 * 3 / 4 = 3*3 = 9
December 3, 2015

Maths
2 w + 2 (w+5) = 26 2 w + 5 = 13 2 w = 8 w = 4 w+5 = 9
December 3, 2015

Please Check My Work: College Physics
N is normal force from road m g = N cos T so N = m g/cos T N has inward component = N sin T so inward component of force = m g sin T/cosT = m g tan T Ac = m v^2/R m g tan T = m v^2/R tan T = v^2/( Rg) as you know tan T = 400/(200*9.81) tan T = .204 T = 11.5 degrees
December 3, 2015

Please Check: College Physics
You are welcome.
December 3, 2015

Huh ? horizontal, no g , friction force - 12
F = m a -12 = 8 a a = -1.5 m/s^2 yes 0 = 6^2 + 2 a x 0 = 36 -3 x x = 12 m
December 3, 2015

sms
1.44/16
December 3, 2015

History
I would also choose A although he did want to get home.
December 3, 2015

math/technology
If there are two there are two.
December 3, 2015

physics
2 kg * 9.81 = 19.62 N weight loses (19.62-12.34) = 7.28 N in water 7.28 N /9.81 = .7421 Kg of water displace .7421 kg * 1 m^3/1000 kg = 7.421 * 10^-4 m^3 = volume of mass mass of light fluid displaced = 7.421 *10^-4 m^3 * .78 * 10^3 = .579 kg weight of light fluid displaced...
December 3, 2015

calculus
MITx question ?
December 2, 2015

prealgebra
w and w+3 perimeter = 2 w + 2 (w +3) = 58 4 w + 6 = 58 4 w = 52 w = 13 so 13 by 16
December 2, 2015

Precalculus
2(1-sin^2 T) + sin T = 1 2 - 2 sin^2 T +sin T - 1 = 0 -2 sin^2 T + sin T +1 = 0 2 sin^2 T - sin T - 1 = 0 let z = sin T 2 z^2 - z - 1 = 0 (2 z +1)(z-1) = 0 z = -1/2 or z = 1 so sin T = -1/2 gives T = 150 deg or -30 deg sin T = 1 at 90 deg
December 2, 2015

Calc 3
Do you know about divergence and curl ? I have a sneaking suspicion that the divergence and curl (no sources or sinks and no vortices with singularities at the origin) are zero and the flux and line integral around the closed surface are zero.
December 2, 2015

math
12 by 8 by 5 five is the height because in vertical plane. 12 by 8 is the top and bottom. Sketch a drawing of it !
December 2, 2015

chem.
Fe = 56 g/mol 3 O = 3*16 = 48 g/mol so a mol of Fe2O3 is 160 grams and a mol of Fe is 56 grams 3 g Fe = 3/56 mol Fe that will give me half as many mols of Fe2O3 so 3/112 mols Fe2O3 (3/112) * 160 = 4.29 grams of Fe2O3 ========================
December 2, 2015

Physics
force = change on momentum/change in time = .045 * 59 / .001 = 2655 Newtons
December 2, 2015

MATH SUPER URGENT!
50 * 20 = 1000 strip width = s interior dimensions (50-2s)(20-2s) = half original = 500 1000 - 140 s + 4 s^2 = 500 so 4 s^2 - 140 s +500 = 0 s^2 - 35 s + 125 = 0 s = [35 +/- sqrt (1225-500) ]/2 s = [35+/- 26.92 ] /2 s = 30.96 or 4.04 must be 4.04 because strips of 31 each end...
December 2, 2015

Algebra
d = 100 - q 25 q + 10 d = 2140 25 q + 1000 -10 q = 2140 15 q = 1140 q = 76 so d = 24
December 2, 2015

Social studies
nope, which is not an advance in technology but simply something you do.
December 2, 2015

algebra
Huh, what you typed is not true.
December 2, 2015

Algebra
2x -5x -11 >/= 4x + 17 -3x >/= 4x + 17 0 >/= 7x + 17 7x </= -17 x </= -17/7
December 2, 2015

Pre Calc
http://www.jiskha.com/display.cgi?id=1449008243
December 2, 2015

Pre Calc
I think I did this yesterday 5, 12, 13 triangle cos^2 - sin^2
December 2, 2015

MATH
8 log5(x) + 4 log5(y)
December 2, 2015

MATH
log5 (x^2y)^4 4 log5(x^2y) 4 [ log5 (x^2)+ log ( y) ] 4 [ 2 log5 (x)+ log ( y) ]
December 2, 2015

science
By the way I did all this as if a kg was a force If you need Newtons and Newton meters, multiply final answers by 9.81
December 2, 2015

science
get end forces up first beam kg = 6*1500 = 9000 kg at center forces F1 up at left and F2 up at right moments about left to get F2 F2*6 = 1000*1.5 + 11000*3 + 3000*4.5 so F2 = 48,000/6 = 8,000 up at right end total mass = (1+11+3)10^3 = 15,000 kg so F1 = 15,000- 8000 = 7,000 up...
December 2, 2015

math
2w+2L any old whole numbers for L and w
December 2, 2015

algebra please explain
-3
December 2, 2015

math
125,000 - 125,000 = 0
December 2, 2015

Mathematics
mean = 165 defective if <156.2 variance = 16 so sigma = sqrt 16 = 4 (did you notice that?) then use Davidlane http://davidmlane.com/hyperstat/z_table.html I get 0.0139 or 1.39 percent
December 2, 2015

Mathematics
mean = 165 defective if <156.2 variance = 16 so sigma = sqrt 16 = 4 (did you notice that?) then use Davidlane
December 2, 2015

Social Studies
true, Nederlands
December 2, 2015

Social Studies
yes
December 2, 2015

Social Studies
as I remember you are right :)
December 2, 2015

Science
how wide has nothing to do with this Upstream speed = 8.9 sin T - 2.4 if we do not want to go upstream, that must be zero so 8.9 sin T = 2.4 T = 15.6 degrees
December 2, 2015

Social Studies
yes, Catholic
December 2, 2015

Social Studies
Yes, center is Andes and Jungle :)
December 2, 2015

Social Studies
No idea, assume you know
December 2, 2015

Social Studies
yes, that is what missionaries do.
December 2, 2015

Math
Amy if there are F friends, then each gets 40/F say you had 4 people and 40 grapes each would get n = 40/4 = 10 grapes
December 2, 2015

Math
n = 40/f
December 2, 2015

Physics
20 * x = 10 (1.08 -x) 20 x + 10 x = 10.8 30 x = 10.8 x = .36 so .36*10^-10 = 3.6 * 10^-11 meters
December 2, 2015

History
There were no term limits for presidents when I started voting. That was after George Washington rode off into the sunset. He did start a tradition of term limits, but there was no law and in fact FDR served more than two before and during WW2.
December 2, 2015

Algebra 2
log3 (x) = 9 well what I would do is 3^(log3(x)) = x = 3^9 same for #2 3) e^lnx = x = e^2 Just one more step from what you showed
December 2, 2015

math
6.3
December 2, 2015

Math - are you sure?
Do you really mean? x+2y+z=1 -x+y+0z=4 4x-0y+3z=-1
December 2, 2015

Physics
Hi = 1.6 u = 6.4 cos 65 forever = x coordinate Vi = 6.4 sin 65 initial Vertical problem: v = Vi - 9.81 t h = Hi + Vi t - 4.9 t^2 so 0 = 1.6 + 5.8 t - 4.9 t^2 or 4.9 t^2 - 5.8 t - 1.6 = 0 t = [ 5.8 +/- sqrt (33.64 + 31.36)]/9.8 t = (5.8 +/- 8.06)/9.8 we want + answer t = 1.41 ...
December 2, 2015

Maths
x^2 = 2 y x = +/- sqrt (2y)
December 2, 2015

7th Math
Er 1.7 *10^22 P 1.3*10^22 Ha 4*10^21 Ma 3*10^21 Ce 9 * 10^20
December 2, 2015

7th Math
You are welcome.
December 2, 2015

7th Math
1. right 2. right , right
December 2, 2015

English
yuuk, insensitive Easy for you to say :)
December 2, 2015

English
radiant star looks like a symbol AND a metaphor to me Oh come on - B
December 2, 2015

English
Note " ... device used to adjust ...." so I think C I also think the metaphor stinks.
December 2, 2015

English
Unfortunately I have to agree with Sid,V note: " ... there comes a time ... "
December 2, 2015

Maths
2 w + 6 t w = 11 w (2 + 6 t) = 11 w = 11 / (2 + 6 t)
December 2, 2015

ntc
http://www.gregthatcher.com/Mathematics/GaussJordan.aspx
December 2, 2015

Oxford, maths
x + y = 10 y = -x + 10 if x = 0 , y = 10 if y = 0 , x = 10 draw line through those two intercept points
December 2, 2015

math
2/3 (12) = 8 4.5 * 12 = 54 54 + 8 = 62
December 2, 2015

Pre-Cal
sin 42 = h/400
December 1, 2015

math
cross section area = pi(.9)^2 - pi(.7)^2 volume = 2.5 * pi (.81-.49)
December 1, 2015

Algebra
slope = (72-18)/8-2) = 54/6 = 9 9 = (y-18)/(x-2) so y-18 = 9(x-2)
December 1, 2015

Math
w/L = 2/5 4/10 = 2/5
December 1, 2015

Math
v = rowing speed u = current speed 2 miles = (v+u)(20/60) 2 miles = (v-u) (1) ============================ then 2 = v/3 + u/3 2/3 = v/3 - u/3 ------------------ 4/3 = 2 u/3 u = 2 etc
December 1, 2015

Math
http://davidmlane.com/hyperstat/z_table.html
December 1, 2015

Geometry
b can NOT be 45 degrees and the magnitude MUST be bigger than 24.1 north = 10 + 20 cos 45 = 24.1 agree east = 20 sin 45 = 14.1 agree mag = sqrt (24.1^2+14.1^2) = 27.94 tan deg e of n = 14.1/24.1 so deg e of n = 30.3 degrees East of North
December 1, 2015

Algebra 2
a = k/b 2 = k/15 k = 30 a = 30/6 a = 5
December 1, 2015

Pre Calc
(x-2)(x-2) (-2x-1)(x+1) = 0 roots 2 2 -1/2 -1
December 1, 2015

Algebra
w(w+2) = 224 w^2 + 2 w - 224 = 0 (w-14)(w+16) =0 w = 14
December 1, 2015

Algebra
2 L + 2 w = 58 so L + w = 29 and L=29-w w (29-w) = 204 29 w - w^2 = 204 w^2 - 29 w + 204 = 0 w = [ 29 +/- sqrt(841-816) ] / 2 w = [ 29 +/- 5 ]/2 w = 34/2 = 17 L = 12 that works or L =17 and w = 12
December 1, 2015

MATH
0.40 x = 56 x = 56/.4 = 560/4
December 1, 2015

please check typing
What you wrote makes no sense to me beginning with is it a quadrilateral (4 sides) or a triangle (3 sides)
December 1, 2015

Snap - 3rd grade technique
Many third grades do division the way you and I learned, but more and more are using other methods that link into common core. I am not sure what methodology this student might be learning.
December 1, 2015

3rd grade math
well, divide by two to get what she drives each day 752/2 = ? I am not sure how your class does division 7/2 = 3 remainder 1 thus 5 becomes 15 regrouping 15/2 = 7 remainder 1 thus 2 becomes 12 regrouping 12/2 = 6 NO remainder :) so I get 376 b) if she can do the whole trip in ...
December 1, 2015

physics sound waves
lam = wavelength second lowest with open ends: lam = Lo second lowest with closed end lam = 4/3 Lc f proportional to 1/Lam so f open = k/Lo and f closed = 3k/4Lc difference frequency = k (1/Lo -3/4Lc) third lowest open Lam = (2/3) Lo third lowest closed Lam = (4/5) Lc f open...
December 1, 2015

science help
NO ! similar charges repel
December 1, 2015

science help
LOL, like charges repel
December 1, 2015

science check please
Hey, hang on ! THINK!!! The gravitational field of earth pulls the air molecules toward the center of earth, just like it pulls water molecules in the ocean toward the center. As a result, as you go toward the center of earth, either in air or in water, you get more and more ...
December 1, 2015

Pre Calc
cos x + sin x LOL, I just looked at it and wrote it because sin x/tan x = sin x /(sin x/cos x) = cos x etc
December 1, 2015

Pre Calc
2 z^2 - 3 z + 1 = 0 (2z-1)(z-1) = 0 z = 1/2 or z = 1 so when is sin x = 1/2 ? and when is sin x = 1 ?
December 1, 2015

Precalculus
2) log(base7)5=7-6x 5 = 7^(7-6x) = 7^z log 5 = z log 7 z = .827 7 - 6 x = .827 6 x = 6.1729 x = 1.0288
December 1, 2015

Precalculus
4) 4^(x-5)=8^(x+2) (2^2)^(x-5) = (2^3)^(x+2) 2^(2x-10) = 2^(3x+6) 2x-10 = 3x+6 x = -16 agree
December 1, 2015

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