Saturday
June 25, 2016

Posts by Damon

Total # Posts: 26,371

math age problem
(r-2) , r , (r+8) 3 r + 6 = 60 3 r = 54 r = 18 so 16 , 18 , 26
February 17, 2016

whoops
sorry, use Reiny solution
February 17, 2016

Trig
cos 52 = (h-10.5) /12
February 17, 2016

algebra
one triangle is 20 by 30 the other is 30 by 30 sqrt(30^2+30^2) + sqrt(20^2+30^2)
February 17, 2016

chemistry
well, first it only has one electron. The spectrum gives you possible energy levels (states or orbit radius) for that electron.
February 16, 2016

math
h = 1000 x = sqrt (1250^2 - 1000^2) = 750 meters horizontal r = distance (hypotenuse) r^2 = h^2 + x^2 2 r dr/dt = 0 + 2 x dx/dt so dr/dt = (x/r) dx/dt = (750/1250)(800)
February 16, 2016

math
38 = 2 * 19 57 = 3 * 19 so 2/3
February 16, 2016

Algebra
Yes, an hour, 60 min
February 16, 2016

Algebra
stan speed = s lawns/min Hilda speed = 2s lawns/min (s + 2s) = total speed in lawns/min so (s + 2s) (20 min) = 1 lawn 60 s = 1 s = 1/60 lawns/min or 60 min/lawn
February 16, 2016

Algebra
80 t = 125 (t-1) 125 = 45 t t = 2.7777 hours or 2 hours and 47 min for car 1 and 1 hour and 47 minutes for car 2 check 80 * 2.777 = 222 125 * 1.777 = 222 good so 1 hour and 47 minutes
February 16, 2016

Algebra
420 - 20 = 400 420 + 5 = 425 so 400</= T </= 425
February 16, 2016

Algebra
8 parts total (3/8)(568) alcohol (5/8)(568) acid
February 16, 2016

Algebra
.04 x + .06 ( 67000-x) = 3440
February 16, 2016

math
I guess it starts at 0 height h = a x^2 + b x 148 = a (1)^2 + b(1) 272 = a(2)^2 + b(2) b = 148 - a 272 = 4 a + 2 (148-a) 272 = 4 a -2 a + 296 2 a = -24 a = -12 (should be 16 on earth but anyway) b = 148 +12 = 160 so h = -12 x^2 + 160 x if x = 6 h = -12*36 + 160(6) = 528
February 16, 2016

Algebra
f = 4 t 5 f + 10 t = 1050 so 20 t + 10 t = 1050 30 t = 1050 t = 35 tens
February 16, 2016

Help please? Math 141 (Pre-Cal)
as t gets huge the 84 and the 28 are small potatoes s ---> 51/3 = 17 16.5 = (51 t + 84)/(3t+28) solve for t
February 16, 2016

Math
are you doing geometric sequences maybe? 32 32*4.5 32*4.5^2 32*4.5^3 32 144 648 2916
February 16, 2016

Physics
Torque = I alpha Tension in line = T weight = m g = 1 * 9.8 = 9.8 N so 9.8 - T = 1(4.5) T = 5.3 N or kg m/s^2 torque = T * R = 5.3 R Nm or kg m^2/s^2 so 5.3 R kg m^2/s^2 = I alpha but a = alpha R so alpha = a/R so 5.3 R^2 kg m^3/s^2 = I kg m^2 * 4.5 m/s^2 I = 5.3 * .45^2 /4.5...
February 16, 2016

physics
assuming that then v = dx/dt = 2 A t + B a e^(at) acc = dv/dt = 2 A + B a^2 e^(at) now constraints at t = 0 -2 = B so 4 = -2 a a = -2 so in fact x = A t^2 -2 e^(-2t) v = 2 A t + 4 e^(-2t) acc = 2 A -8 e^(-2t) now at t = .2 , v = 5 so 5 = 2 A(.2) - 8 e^-.4 5 = .4 A - 5.36 A = ...
February 16, 2016

?
do you mean x = A t^2 + B e^(at) ?
February 16, 2016

Social Studies (Check, Please!)
Typo in #2 fight, they were old enough to fight. You mean VOTE
February 16, 2016

jewellry
Amma said to do what she typed, y = -3/x + 1
February 16, 2016

Math-asymptotes
ok if it is y = -(3/x) + 1 then clearly when x -->0 this becomes huge positive or negative depending on if x is positive or negative. That is the poit of vertical asymptotes as x becomes huge positive or negative, y---> 1 horizontal
February 16, 2016

huh?
do you mean y = -3/(x+1) or what you typed?
February 16, 2016

Math
2 cups / 36 cookies = x cups/ 60 cookies
February 16, 2016

Math
cran/gran = 1/3 1/3 = 3/x x = 9
February 16, 2016

Algebra
24.5 * 10^4 = 2.45 * 10^5 so yes, b
February 16, 2016

Algebra
correct, 100 is not twice ten
February 16, 2016

Algebra
a is actually 4.01 * 10^-5 so yes it is the biggest
February 16, 2016

Algebra
yes
February 16, 2016

Algebra
right
February 16, 2016

Math
You are welcome
February 16, 2016

Math
yes
February 16, 2016

Math
8/3 * 4/3 = 32/9 = 27/9 + 5/9 = 3 + 5/9 = 3 5/9
February 16, 2016

Math
8/8 + 1/8 = 9/8 4/2 + 1/2 = 5/2 so 9/8 * 5/2 = 45/16 = 32/16 + 13/16 = 2 13/16
February 16, 2016

Math
1 1/2 * 2 3/5 3/2 * 13/5 39/10 3 9/10
February 16, 2016

URGENT! Due soon and I used 8 of 10 attempts
.145 = (1/2)^n log .145 = n log .5 n = 2.786 half lives 2.786 * 5730 = 15963 = 1.5963*10^4 years
February 14, 2016

precalc11
check 700 * 1.0356^30 = 1999.99
February 14, 2016

precalc11
2000 = 700 x^(2000-1970) 2.857 = x^30 log 2.857 = 30 log x log x = .0151977 x = 1.0356 so 3.56 percent per year
February 14, 2016

Physics
total mass = 8.10+3.90 = 12.0 kg gravitational force = 3.90*9.81 = 38.3 N f = m a so a = 38.3/12 = 3.19 m/s^2 the 38.3 - T = 3.90 a = 3.90(3.19) T = 38.3 - 12.4 = 25.9 Newtons
February 14, 2016

Physical science
G = 6.67 * 10^-11 so 6.67*10^-11 * 1215^2 /(31)^2
February 14, 2016

Physical science
G M1 M2 /d^2
February 14, 2016

MATH
well, I guess we could use 6 - 2x for y 3 x + 2 (6-2x) = 6 3 x -4 x + 12 = 6 x = 6 then y = 6 - 2(6) = -6
February 14, 2016

Chemistry
HNO3/CU(NO3)2 = 4 mols /1 mol so 6/x = 4/1 4 x = 6 x = 1.5
February 14, 2016

Math
if x>/=0, y = 2-2e^-x if x <2, y = -1
February 14, 2016

science chemistry
note, absorbed high energy radiated much lower energy therefore, energy of atom went up.
February 13, 2016

science chemistry
http://www.jiskha.com/display.cgi?id=1455410600
February 13, 2016

science chemistry
Now I just did one using the same relationships between frequency, period, speed of light, wavelength and energy. This one is the same.
February 13, 2016

Chemistry
E = h f 3.2 * 10^-19 = 6.6*10^-34 f f = .485 * 10^15 Hz T = 1/f = 2.06 * 10-15 seconds if c = 3*10^8 m/s lambda =c T =3*10^8 * 2.06*10^-15 = 6.19 * 10^-7 meters = 619 * 10^-9 meters
February 13, 2016

math
Tara, the legs are 90 degrees from each other
February 13, 2016

math
north 55*3 west 65 * 3 hypotenuse = 3 sqrt (65^2+55^2)
February 13, 2016

Chem
4 mols of NH3 for every 3 of O2 so 4 4/3 = 8/6 so 6 of O2 also 4/2 = 8/4 so 4 of N2 4/6 = 8/12 so 12 of H2O I am getting bored :( 4/2 = 2/1 so 2 of NH3 3 of H2O enough already
February 13, 2016

physics
LOL, well we all know that pressure is density * v^2 but we better answer the question anyway. pressure = force/area = mass * acceleration / area^2 = M L/T^2 / L^2 = M /(L T^2) density = M/L^3 velocity = L/T so density * velocity^2 = M/L^3 *L^2/T^2 = M (L T^2) which sure ...
February 13, 2016

Physics
Google "Lagrange point"
February 13, 2016

MATH>:(
space 1, any of 7 space 2, any of 6 space 3, any of 5 etc 7! = 7*6*5*4*3*2*1 = 5040
February 11, 2016

Pre-Calc
(x+a)(x+a) x = -a or x = -a :) -a,-a (-a)^2 + 2a(-a) + a^2 a^2 - 2 a^2 + a^2 = 0 would you believe?
February 11, 2016

Math
height = 4 cm length = width = x-8 (x-8)(x-8)4 = 324 x^2 -16 x + 64 = 81 x^2 - 16 x - 17 = 0 (x-17)(x+1) = 0 well it is not -1 so x = 17 17 by 17
February 11, 2016

been there, done that
did that above
February 11, 2016

Linear Algebra
Here you go: http://en.wikipedia.org/wiki/Linear_algebra
February 11, 2016

Linear Algebra
By the way , that is algebra, and it is linear, but it is not "linear algebra" Google "linear algebra " :)
February 11, 2016

Linear Algebra
(Y2-Y1)/(X2-X1) = (1+3) /(1+2) = 4/3
February 11, 2016

Linear Algebra 8; Slope-Intercept Form
Now that was not even linear, never mind linear algebra LOL
February 11, 2016

Linear Algebra 8; Slope-Intercept Form
7^2 + x^2 = 11^2 49 + x^2 = 121 x^2 = 72 = 36 * 2 x = 6 sqrt 2 = 8.48528 which is around 8.5
February 11, 2016

General physics
x direction Fx = 2.8 + 4 = 6.8 Fy = -3.5 - 11.5 = - 15 Ax = 6.8/4.6 Ay = -15/4.6 |A| = sqrt (Ax^2 + Ay^2)
February 10, 2016

Math
well, it looks like y depends on x so if x = 6 then y = 60 - 3
February 10, 2016

algebra
Anyway, my way is more fun !
February 10, 2016

algebra
I GET x^2 + 6 x -7 facor that (x+7)(x-1) so -7 and 1 the end finally
February 10, 2016

algebra
I get (x-2)(x^3 + 8 x^2 + 5 x - 14) now 14 is either 14 and 1 or 7 and 2 2 does not work this time :( try -2 -8 + 32 -10 - 14 =-24+24 = 0 CARAMBA !!! X = -2 IS A SOLUTION SO (x+2)(x-2) so far divide x^3+8x^2+5x-14 by (x+2)
February 10, 2016

algebra
well, 28 has to have factors 2 14 4 7 lets try 2 and -2 16 + 48 -44 - 48 +28 lo and behold = 0 so x = 2 is a solution and (x-2) is a factor so divide that mess by (x-2) I get with long division (to be continued :)
February 10, 2016

alebra
This is a circle x^2 + 8 x + 16 + y^2 -8y +16 = 49+32 = 81 = 9^2 (x+4)^2 + (y-4)^2 = 9^2 center at x = -4 , y = +4 , radius 9 sketch it Now do the problem when x = 0 y^2 - 8 y - 49 = 0 y = [ 8 +/- sqrt (64+196) ]/2 y = 4 (of course) +/- 6.32 when y = 0 x^2 + 8 x - 49 = 0 x...
February 10, 2016

Algebra 2
LOL 90 + 45 + other angle = 180 so other angle = 45 In other words we know from the start that it is an isoceles right triangle. sides are 8 hypotenuse is 8 sqrt 2 because 1^2 + 1^2 = 2^2 :)
February 10, 2016

Math
A and A-2 A + A - 2 = 24 2 A = 26 A = 13 B = 11
February 10, 2016

Physics
I asks where the potential is zero, not necessarily where the force is zero You can add the potential due to the two charges on the x axis V = k Q/R1 = k Q1 /|x-xq| forget k and the 10^-6 because they are the same for both and we are looking for zero I will do the - 2 first -2...
February 9, 2016

Spelling
Now Rahul, do you get that (a^2-b^2) = (a+b)(a-b)
February 9, 2016

Spelling
ROTFL How can you make a cohesive sentence using the word cohesive? IS one :) I am not sure about the Elmer's sentence, would have used "adhesive". However the cohesive group works.
February 9, 2016

Algebra
what you are missing is a rule to remember a^2-b^2 = (a+b)(a-b)
February 9, 2016

Algebra
(x^2-a^2)/(x-a) = (x-a)(x+a) /(x-a) = (x+a)
February 9, 2016

Algebra
x^2 - a^2 = x^2 - a^2 (x-a)^2 = x^2 - 2 a x + a^2 quite a different animal
February 9, 2016

math
-4^.000001 = -1.000001386 :) it really means - (4)^0
February 9, 2016

physics
Tension = T T sin 20 = weight = m g so T = m g/sin 20 = 28.7 * m if g = 9.81 m v^2/R = T cos 20 = 28.7 m (.94) so v^2/R = 27 v^2 = 27 R R = 1.5 cos 20 = 1.41 meter so v^2 = 27(1.41) v = 6.17 m/s circumference = 2 pi R = 8.86 meters time around = 8.86 meters/6.17 m/s = 1.44 ...
February 9, 2016

Math
term n = 32 (1.5)^(n-1) when n = 1 term 1 = 32 (1.5)^(1-1) = 32(1.5)^0 but anything^0 = 1 so first term is 32 when n-1 = 0 32 48 72 108 162 243 364.5 546.75 etc
February 9, 2016

Math
48 - 32 = 16 = d 108 - 72 = 36 = d d is NOT CONSTANT SO NOT arithmetic !!!!!!! but 48/32 = 1.5 = r 108/72 = 1.5 = r SUCCESS ! r, the ratio, is 1.5, GEOMETRIC
February 9, 2016

Physics
m g h = 981 Joules 245 Joules is lost heating the pavement 981 - 245 = 736 Joules is left at the bottom That 736 Joules is all Kinetic Energy now because m g h = m g * 0 = 0 245 Joules was lost. I do not know the time so can not tell you the rate of energy loss (power) ...
February 9, 2016

physics
E dot A = 3640 * .166 * .72 = yes, 435 N m^2 /C If the plane is turned 90 degrees, none of the E field goes through it. E dot A = 0 The answer is ZERO
February 9, 2016

Algebra
Huh? They are all the same.
February 9, 2016

math, ratios
the number of pairs of shoes to number of shoes is 1/2 I can trade 29 dofrangles for every 30 fringbats. These are adjacent country currencies on the island of Qfrink. In fact I can get one dollar for every 29 dofrangles and one dollar for every 30 fringbats. there are 52 ...
February 9, 2016

Chemistry
Well, you can find the electric field E due to charge 1 at charge 2, then multiply that field by charge 2 to find the repulsive force (note, same sign charge repels, different signs attract) HOWEVER, normally you use Coulombs Law F = k Q1 Q2 / r^2 ( Google "Coulomb's ...
February 9, 2016

Chemistry
I guess that is CuC2 hydrated with x H2O CuC2 = 63.5 + 24 = 87.5 grams/mol so 1.6045 grams * 1 mol/87.5 grams = .0183 mol of CuC2 H2O = 18 grams/mol we have how many mols of H2O? 1.9045 - 1.6045 = 0.3 grams H2O so 0.3 / 18 = .01667 mol H2O looks like about as many mols of H2O ...
February 9, 2016

pysics
force times distance in the direction of the force = 20 N * 1 meter = 20 Joules
February 9, 2016

physics
omega = sqrt (k/m) = sqrt (12.6/.0107) = 34.3 radians/s x = .378 cos (omega t) v = -.378(34.3) sin (omega t) when x = .378/2 cos(omega t) = .5 then omega t = 60 degrees = pi/3 radians then sin (omega t) = .866 (I am ignoring signs here, we need speed not velocity) v = .378 * ...
February 9, 2016

Physics
positive v from 0 to 2 negative v from 2 to 5 positive v from 5 to infinity parabola holds water, crosses below x axis between 2 and 5 vertex at t = 3.5
February 9, 2016

Physics
ans part 3 is from - 30 to + 2 = +32
February 9, 2016

Physics no part 4
part 4 use absolute value of distance is 52 + 20 = 72
February 9, 2016

Physics
I assume that we do not do negative time so v is positive for 0<t<2 and for t >5 when t = 0, x = -30 when t = 2, x = 22 when t = 4, x = 2 so 28 from 0 to 4 (part 3)agree part 4 +52-20 = 32
February 9, 2016

Physics
dx/dt = 6 t^2 - 42 t + 60 = 6 (t^2 - 7 t + 10) = 6 (t-2)(t-5) negative from 2 to 5 (Not 3 to 5)
February 9, 2016

Calculus
c = cups/day p = pennies/cup dc/dp = -2/5 so c = -(2/5) p + constant when p = 50, c = 40 so 40 = -2*50/5 + constant constant = 60 and c = -(2/5) p + 60 now you can make that p = 5n if you choose where n is an integer number of nickels c = -2 n + 60
February 8, 2016

physics
Now I did the grasshopper, same deal
February 8, 2016

physics
h = Vi t - 4.9 t^2 .587 = Vi t - .5*9.81 t^2 but t at top is Vi/9.81 where 0 = Vi - g t .587 = Vi^2/9.81 - .5 * 9.81 (Vi^2/9.81^2) .587 = .5 * Vi^2/9.81 Vi = 3.39 m/s vertical up Vi = speed * sin 58 so speed = 4.00 m/s part a u = 4.00 cos 58 = 2.12 m/s time in air = 2 * rise ...
February 8, 2016

Math
out of n, n-6 were gotten right so let's find n-6 Jack alone got 40 -32 = 8 Jill alone got 50-32 = 18 so in total alone they got 26 plus they got 32 together 26 + 32 = 58 right total plus the 6 wrong = 64
February 8, 2016

maths
every year multiply value by 0.90 1 year= 20,000 * .9 2 years 20,000 * .9^2 3 years 20,000 * .9^3 so part (c) n years 20,000 * .9^n It is like reverse compound interest, it will not go down 2,000 every year, but only 10% of its MOST RECENT value every year so 2 years 20,000...
February 8, 2016

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