Sunday
February 1, 2015

Posts by Damon


Total # Posts: 20,453

Algebra 2
Intersection of a hyperbola with an ellipse, cool 2 x^2 - 5 y^2 = 1 2 x^2 + 10y^2 = 136 --------------------subtract -15 y^2 = -135 y^2 = 9 so y = +/-3 x^2 = 68-45 = 23 so x = +/-sqrt(23) (sqrt 23 , 3) (sqrt 23 , -3) (-sqrt 23 , 3 ) (-sqrt 23 , -3)
January 11, 2015

math
The trick is: Out of every four bagels one is sesame and three are plain so that sesame/plain = 1/3 sesame/all = 1/4 = .25 = 25% plain/all = 3/4 = .75 = 75% (1/4) 24 = 6 sesame (3/4) 24 = 18 plain
January 11, 2015

Calculus
f' = 1/x^2 at x = -3, f = 1/3 at x = -1/2, f = 2 slope = (2 - 1/3)/(-1/2 + 3) = (5/3)/(5/2) = 2/3 where is the derivative = 2/3 ? 1/x^2 = 2/3 x^2 = 3/2 x = +/- sqrt (3/2) yes B
January 11, 2015

Math
first equation y - x/2 = 5 2 y - x = 10 second equation -x + y/5 = -13 y - 5x = -65 2 y - 10 x = -130 so two equations 2 y - x = 10 2 y - 10 x = -130 --------------------subtract 9 x = 140 x = 15.56 y = 5 + x/2 = 12.78
January 11, 2015

Calculus
yes, v = 6 t - 3 t^2 dv/dt = 0 at max or min = 6 - 6 t so max or min at t = 1 max or min? d^2v/dt^2 = -6 so max what is that max v at t = 1 v(1) = 6-3 = 3 so C.
January 11, 2015

MATH
I think you will have to try various interest rates and graph that function if i = .1 or 10% 6.25 = 5.76 if i = .08 6.25 = 6.24 close to 8%
January 10, 2015

Math
scroll down a bit. I just did that not a good idea to use your real name
January 10, 2015

Polynomials
it is asking if the left is the same as the right look at a (a-b)(a-b) = a^2 -2ab + b^2 Always then b (a+b)(a+b) = a^2 + 2ab + b^2 NOT a^2+b^2 and is ONLY true if a or b is zero same problem with c You have a typo in d but if that is a + sign then true (a+b)(a+b)=a^2+2ab+b^2
January 10, 2015

Math
(4x-1)/[(x+3)(x+4)] * (x+4)(x-3)/(2x-1) when you divide fractions, invert the denominator and multiply (x+4) cancels (4x-1)(x-3) /[ (x+3)(2x-1)]
January 10, 2015

Math
yours (x^2-2x)/(x+1)x (x^2-1)/(x^2+x-6) My work on simplifying the expressions x(x-2)/(x+1) * (x+1)(x-1)/[(x+3)(x-2)] note your sign error in second denominator (x+1) and (x-2) cancel x(x-1) / (x+3)
January 10, 2015

Calculus
2^1 +2^1 *2^1 + 2^1* 2^2 ..... 2^1*2^(n-1) is 2 + 2*2 + 2 *2^2 .... note 2^1 * 2^(n-1) = 2^n 2^1 =2 = a 2 = r sum from i = 1 to n = 2 ( 1-2^n)/(1-2) = -2 (1-2^n) =2^(n+1) - 2
January 10, 2015

calculus
Do you mean from 0 to 5 and from 0 to 6 ? if so 2 (x^2 -3 x) at 5 - at 0 = 2 (25 - 15) - 0 = 20 at6 it is 2 (36-18) = 2*18 = 36
January 10, 2015

calculus
what is the derivative of (5/7)x^7 ? what is the derivative of -x^(-2) ?
January 10, 2015

Physics
period = T = 60 seconds/26 = 30/13 f = 1/T = 13/30 A = 3.9 cm y = -3.9 cos (2 pi t/T) because y = -3.9 when t = 0 y = - 3.9 cos (26 pi t/30)
January 10, 2015

Math
I can not simplify it but f(x) = -3(x^2+4x+4) -x-1 = -3 x^3 -12 x -12 - x - 1 = -3x^2 - 13 x -13 sure enough f(x) = [(x-2)(x+1)] / [ (3x+1)(x+1) ] = (x-2)/(3x+1) we win again
January 10, 2015

Math
(x-2)(x+1)/(x+1) = x-2 = g(x) (x-4)(x+3)/(x+3) = x-4 g(x) = (x-2)(x-4)/(x-2) = x-4 also
January 10, 2015

math
13,000 = 6,000 +.05(x-20,000)
January 10, 2015

maths
took me 40 http://www.jiskha.com/display.cgi?id=1420913304
January 10, 2015

maths-6th grade
sorry I took so long, had a grandson's hockey game in the middle of that.
January 10, 2015

maths-6th grade
t x 0 0 1 20 2 10 3 30 4 20 5 40 6 30 7 50 8 40 9 60 10 50 11 70 12 60 13 80 14 70 15 90 16 80 17 100 18 90 19 110 20 100 21 120 22 110 23 130 . . . 40 200 averages 5 meters/min
January 10, 2015

maths algebra
x/2 red x/d blue x - x/2 - x/d = x(1/2 - 1/d) yellow
January 10, 2015

math
-2 -2*-3 = 6 6*-3 = -18 -18*-3 = 54 54*-3 = -162 etc
January 9, 2015

math
oh 486 + 440
January 9, 2015

math
area of cube = 6*49 subtract pi (3.5^2) so cube area painted = 294 - pi(3.5)^2 side area of cylinder = 20 ( 7 pi) end areas = 2 pi(3.5^2) but delete one so total cylinder area =140 pi+pi(3.5^2) total = 294-pi(3.5)^2+140pi+pi(3.5)^2 = 294 + 140 pi = 294 + 20(22) = 294+440 = 734
January 9, 2015

math
a + 12 d = 159 a + 19 d = 264 --------------- 7 d = 105 d = 15 a = 159-12(15) = -21
January 9, 2015

Math
[5(x+1) +2(x-1)]/(x^2-1) = -6 5x+5 +2x-2 = -6x^2 + 6 6 x^2 + 7 x - 3 = 0 (2x+3)(3x-1) = 0 x = 1/3 or -3/2
January 9, 2015

Math
(3x+1)/[2(x+1)(x-1)]+2(x+1)/[2(x-3)(x-1)] [(3x+1)(x-3)+(x+1)^2 ]/[(x^2-1)(x-3)] [ 3x^2-8x-3 +x^2+2x+1 ]/[(x^2-1)(x-3)] [4x^2-6x-2]/[(x^2-1)(x-3)] 2[2x^2-3x-1] / [(x^2-1)(x-3)]
January 9, 2015

math
along diameter 28/4 + 1 = 8 around semicircle pi D/2 = 14 pi = 14(22/7) = 44 meters or 11 spaces none at ends, already there, so 11-1 = 10 total of 18
January 9, 2015

History
... and it was Turkey, Greece and Iran in the Middle East by the way. ... and what about Eastern Europe - Poland, Hungary, etc
January 9, 2015

math
p pencil p - 15 = rulers 3(p-15) = books total = p + p - 15 + 3 p - 45 = 5 p - 60
January 9, 2015

math
yes 12+3 = 15 :)
January 9, 2015

U.S History
Google history of US presidential cabinet
January 9, 2015

Science - Please answer as soon as possible
I would pick b.
January 9, 2015

physics
weight down = mass times centripetal A down mass cancels, does not matter g = v^2/R
January 9, 2015

incomplete
You need to know the magnitude of the pulling force. If mass and coef of friction are given and the velocity is constant then it is horizontal force = F cos 30 = m g (mu-sin 30) W = F cos 30 * 20*10^3 J
January 9, 2015

LA - 1 question
1.
January 9, 2015

Geometry
A is your statement of the problem B subtract two from both sides C multiply both sides by 6
January 9, 2015

Social Studies help
If you look at the products on that tree, it looks like we all use coal in one way or another :)
January 9, 2015

Social Studies help
http://www.coaleducation.org/lessons/twe/bytree.htm
January 9, 2015

Math
29500 + .041*128500
January 9, 2015

Math
Yes cos = 0 sin = 1
January 9, 2015

physics
882 *3.8/9.8
January 9, 2015

Physics and Math
ball rolls distance 1 + x loss of height = (1+x)sin 30 = .5(1+x) loss of potential energy = 1*9.8*.5(1+x) gain of potential energy = .5 k x^2 = .5 x^2 so 9.8(1+x) = x^2 x^2 - 9.8 x - 9.8 = 0 x = [ 9.8 +/-sqrt(96+39.2)]/2 x = (9.8+/-11.6)/2 x = 10.7
January 8, 2015

Incomplete
So what is the question ?
January 8, 2015

MNHS_HELP
I drew 6 8*8 5*5 3*3 2*2 two 1*1
January 8, 2015

English
I suppose you could say the social context was very lonely, just the nut case and the poor old man. In other words isolated.
January 7, 2015

Physics
m g sin theta 4 * 9.81 * (1/2) about 19.6 N
January 7, 2015

Science
Yes, in fact it was Thorium.
January 7, 2015

Science
it depends on what medium to what medium. Fastest in a vacuum
January 7, 2015

Math
yes, with some left over.
January 7, 2015

math
1260 miles (6 gallons/180 miles) = ?
January 7, 2015

Math
there are more 81 s than anything else
January 7, 2015

Math
I assume you mean: -x^2/4 + 9 x/5 + 2 = y complete the square first multiply by -4 x^2 - 36 x/5 - 8 = y x^2 - 36 x/5 = y+8 x^2 - 36 x/5 + (18/5)^2 = y + 8 + 12.96 (x-18/5)^2 = y + 20.96 so vertex at ( 3.6 , -20.96)
January 7, 2015

adding and subtracting rational
(11*8)/(15*8) + (1*15)/(8*15) = 88/120 + 15/120 = 103/120
January 7, 2015

Physics
infinitely fast, constant acceleration forever m a = m * 9.81 * sin 10.3 so a = g sin 10.3 = 9.81 sin 10.3 so v = (9.81 sin 10.3) t v is proportional to time, forever
January 7, 2015

physics
(T-30)(10 kg) (heat capacity of water) = 5000
January 7, 2015

physics
m v^2/r = m g so m cancels of course, has to be the same no matter how many in the car :) v= sqrt (r g)
January 7, 2015

Physical Science HELP
Zn + I2 ---> ZnI2 the end
January 7, 2015

Math
I assume x/(x^2-3x-4) - 4/(x+1) ????? x/[(x+1)(x-4)] - 4(x-4)/[(x+1)(x-4)] -3x+4 /[(x+1)(x-4)] blows up if x = -1 or x = 4
January 7, 2015

algebra 2
(x+4)(x-1) = 0 y = x^2 + 3 x - 4
January 7, 2015

math
.4 * 50 = 20
January 7, 2015

Math
x = x^2 + xy + x + y 0 = x^2 + y (x+1) y = -x^2/(x+1)
January 7, 2015

math
1 1/4 = 5/4 bags 7 1/2 = 15/2 pounds /bag so (5/4) bags *(15/2) pounds/bag = 75/8 = 9 3/8 pounds
January 7, 2015

math
365.75 km ( 1 hr/133 km) = 2 3/4 hr = 2 hours and 45 minutes
January 7, 2015

Chemistry
F2O3 ??? 2Fe2O3 + 3C --> 4Fe + 3CO2 ??? maybe mols of Fe2O3 = 3.79*10*24 /6.02*10^23 = 6.30 mols Fe2O3 or 12.6 mols Fe Fe is 56 g/mol so 12.6 * 56 = 706 grams Fe `
January 7, 2015

Math
sin 24 = h/30 h = 30 sin 24 = 12.2 ft note - do not climb ladder that barely reaches the eaves.
January 7, 2015

Physic
c = q/v same q on each, call it q so c1 V1 = c2 V2 so V2 = (c1/c2) V1 and V1 + V2 = 1000 V1 + (c1/c2)V1 = 1000 but c1/c2 = 3/6 = .5 so 1.5 V1 = 1000 V1 = 667 V2 = 333 I think you can go back and get q = v c for each
January 7, 2015

Maths
a + d (n-1) a + d = 7 a + 4 d = 22 ------------ -3 d = -15 d = 5 so a = 2 2 , 7 , 12 , 17 , 22
January 7, 2015

math
6 / (1/3) = 6 * 3
January 7, 2015

physics
force = change in momentum/time = (50 kg * 5000 m/s) /s = 250,000 Newtons thrust weight = m g = 60,000*9.81 = 588,600 N no way
January 7, 2015

physics
m = 30/9.81 a) (30/9.81)v = .005 * 300 b) (730/9.81)v = .005 * 300
January 7, 2015

math
4.5 in ( 20 mi/in) = 90 miles 90 miles (1 in/18 mi) = 5 inches
January 6, 2015

physics
(1/2) m v^2 start = m g h at top so m g h = 2 * 10^4 m = 2*10^4 / (9.81*50) = 40.8 kg
January 6, 2015

Science
Probably with carbon 14 dating. http://dwb4.unl.edu/Chem/CHEM869Z/CHEM869ZLinks/www.all.mq.edu.au/online/edu/egypt/carbdate.htm
January 6, 2015

physics
5.72*10^3 * 3.11 * 10^3 = 17.8 * 10^6 = 1.78 * 10^7 Joules
January 6, 2015

Math
30/20 = 1.5 , 90/60 = 1/5 the same 15/20 = 3/4 , 10/15 = 2/3 NOT the same
January 6, 2015

Math
I would say A
January 6, 2015

Science
You are welcome
January 6, 2015

Science
Yes
January 6, 2015

Math
a + d(n-1) a + d (2) = 1985 a + d(7) = 2015 ----------------subtract 0 - 5 d = - 30 d = 6 a + 12 = 1985 a = 1973 1973 + 6(14) = 2057
January 6, 2015

physics
normal force down = 18.4*9.8 - 126 sin 34.1 so friction force = .123 (18.4*9.8-126 sin 34.1) work done by friction - friction force * 20 meters
January 6, 2015

Science
Yes That is all per molecule.
January 6, 2015

4th grd math
3*8 = 24 fish per day 2.5 * 8 = 16 + 4 = 20 eaten so 4 left over each day I guess you do not have seagulls where you live :)
January 6, 2015

Math
15 sandwiches /.75 hr * 3 hr = 60 sandwiches
January 6, 2015

Science
You are welcome.
January 6, 2015

Science
I mean (6/18)*10^23 atoms/gram
January 6, 2015

Science
2 hydrogens, one oxygen in a molecule so three atoms per molecule a mol is 6*10^23 molecules so 18 * 10^23 atoms per molecule a mol weighs 2+16 = 18 grams so (6/18) * 10^23 molecules per gram
January 6, 2015

math
sorry, yes
January 6, 2015

math
39 - 15 = 25 spaces so 25,000 feet 10:11- 10:05 = 6 minutes 25,000/6 = 4167 feet/min a little less than a mile a minute or 60 miles per hour
January 6, 2015

math
1/4 inch to the foot so one inch = 4 feet 6*4 = 24 feet
January 6, 2015

math
14/10 = 1.4 lions per tiger or 14/24 = 7/12 lions (not loins I assume) and 10/24 = 5/12 tigers
January 6, 2015

algebra
there will be a short time on the way up to 28 and a long one for the way down, we want the second minus the first when will h = 28 feet? 28 = 4 + 56 t -16 t^2 16 t^2 - 56 t + 24 = 0 2 t^2 - 7 t + 3 = 0 (2t-1)(t-3) = 0 t = .5 or t = 3 so t = 2.5 seconds above 28
January 6, 2015

Math
dollars / t shirts = dollars per t shirt A 40/16 = 2.50 per shirt B 140/84 = 1.67 per shirt
January 6, 2015

Math
You are welcome.
January 6, 2015

Math
7 d - 4 d - 32 = -8 3 d = 24 d = 8
January 6, 2015

math
oh, I assumed that the 23 was a typo and it meant 2/3
January 6, 2015

math
I think you added 6 girls and get 20 out of 30
January 6, 2015

math
Rodger is right
January 6, 2015

math
3/7 7+10+7 = 24 total students 14 are girls so 14/24 = 7/12 suspect you mean 2/3 are girls (14+x) /(24+x) = 2/3 42 + 3 x = 48 + 2x x = 6 more girls
January 6, 2015

Math
" it is also perpendicular line" should be it is at the intersection of two perpendicular lines.
January 6, 2015

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