Sunday
February 26, 2017

Posts by Damon

Total # Posts: 29,450

Maths trigonometry
tan 30 = 150/x
November 20, 2016

factor of 2
for part b .5 m g (d+x) = .5 k (x)^2 + .5 m v^2 we know d from part a m v^2 = m g d + m g x - k x^2 m v dv/dx = m g - k x dv/dx = 0 at max v k x = m g
November 19, 2016

Physics
You are welcome.
November 19, 2016

Physics
Not that easy m g (d+.23) sin 30 = .5 k (.23)^2 sin 30 = .5 so m g (d+.23)= k (.23)^2 3.2 (9.8)(d+.23) = 443 * .23^2 =========================== for part b m g (d+x) = k (x)^2 + .5 m v^2 we know d from part a .5 m v^2 = m g d + m g x - k x^2 m v dv/dx = m g - 2 k x dv/dx = 0 ...
November 19, 2016

Physics
Slides (d + .23) total m g (d+.23) sin 30 = .5 k (.23)^2
November 19, 2016

math - business
The y intercept is where x = 0 so -12,000 is correct The x axis intercepts are when y, the profit, = 0 that is when x = 2 and z = 15 correct the 15 is from 6000 - 400 x = 0 x = 60/4 x = 15
November 19, 2016

Math Help
probability of no boys = .5^5 so probability of one or more than 1 = 1 - .5^5 = .969
November 19, 2016

calc
so displacement is zero and distance is 5.33 + 15.75 + 10.42 = 31.5 check my arithmetic !!!!
November 19, 2016

calc REPAIR of displacement
v = t^3 - 10 t^2 + 27 t - 18 integral = t^4/4-10t^3/3 +27t^2/2 -18t at 7 integral = -7.58 at 1 integral = -7.58 so displacement = 0
November 19, 2016

calc
I used this to do the numbers: http://www.mathportal.org/calculators/calculus/integral-calculator.php t = 1 to t = 3 int = +5.33 t = 3 to t = 6 int = -15.75 t = 6 to t = 7 int = +10.42 so distance = -21.5 this also says my answer for part 1 should have been 5.33 -15.75+10.42...
November 19, 2016

calc
(t-1)(t-3)(t-6) = 0 so 1 to 3 then 3 to 6 then 6 to 7
November 19, 2016

calc
integrate to find x(1) and x(7) x(7)-x(1) is the displacement vector to find the distance scalar we must know when the particle is moving forward and when back and integrate over those intervals adding absolute values v = t^3 - 10 t^2 + 27 t - 18 integral = t^4/4-10t^3/3 +27t^...
November 19, 2016

Calc
integral of (500-3t) = 500 t - 1.5 t^2 at t = 13, integral = 500(13)-1.5(169) = 6500 - 253.5 = 6246.5 liters
November 19, 2016

Math
integer
November 18, 2016

Math
Are you sure you mean sqrt(-9) ??? That is an imaginary number. Maybe you mean sqrt (25-9) = sqrt (16) which is 4 which is a whole number and an integer
November 18, 2016

Math
5 + sqrt -9 5 + 3 sqt(-1) 5 + 3 i complex
November 18, 2016

math
m < 13 n > 13 p < 5 I think you mean at most 35 people 20 + a <= 35 a <= 15 so no more than 15
November 18, 2016

watch units!
watch out, km/hour given
November 18, 2016

Calc
a = (V2-V1)/(t2-t1) V2 = 90,000/3600 = 25 m/s V1 = 25,000/3600 = 6.94 t2-t1 = 13 so a = 1.39 m/s^2 ====================== d = V1 t + (1/2)a t^2 = 6.94 *13 + .695*169 = 208 m
November 18, 2016

Science
sounds right to me
November 18, 2016

Math
using same web site for normal dist A = .1 M = 72 sd = 9 .1 area is anything below 60.46 If I try bottom .3, anything below a C, I get A = .3 ---> below 67.28, that is the boundary for the HIGHEST D
November 18, 2016

Math
http://davidmlane.com/hyperstat/z_table.html area = .4 mean = 72 SD = 9 .4 are between 71.5 and 72.5 so 71.5
November 18, 2016

physics
total drop = 2.2+ .55 = 2.75 m drop in gravity Potential energy = = 6.95 * 9.81 * 2.75 = increase in spring Pe = (1/2)k x^2 = .5 *k * .55^2 so k = (6.95*9.81*2.75)/(.5*.55*.55)
November 18, 2016

math algebra
cold 1/8 tub/min hot 1/12 tub/min drain -1/7 tub/min so sum 1/8 +1/12 - 1/7 tub/min = 3/24 + 2/24 - 1/7 = 5/24 - 1/7 = 35/168 - 24/168 = 11/168 tubs/min = 168/11 min/tub = 15.3 min
November 18, 2016

Math
false say 1 by 1 1*1 = 1 cm^2 but 1.1 * 1.1 = 1.21 cm^2 .21 is more than .1 :)
November 18, 2016

physics
Ke = (1/2)m v^2 = Pe = (1/2)k x^2 (1/2)m (2v)^2 = (1/2)k (nx)^2 v^2 multiplied by 4 so x^2 multiplied by 4 so 2 times original x
November 18, 2016

Math
mean win = (1+2+3+0+0+0) = 6/6 = $1 so lose .25 per toss so lose $25 for 100 games
November 18, 2016

PRE-CALCULUS
a) 150,000 * 1.054^20 = 320,440.07 check do the others the same way as I showed you in the previous problem below
November 18, 2016

PRE-CALCULUS
r = .12/n where n = times per year a = 5000 * (1+r)^8n eg annual: 5000 * 1.12^8 semi where n = 2 5000 * 1.06^16 quarterly where n = 4 5000 *1.03^32 etc continuous a = 5000 e^.12 t = 5000 e^.96 = 13058.48
November 18, 2016

Math
3*18 = 54 m^2
November 17, 2016

Math
b/g = 7/9 g-12 = b so (g-12)/g = 7/9 9(g-12) = 7g 2 g = 108 g = 54 b = 42 sum = 96
November 17, 2016

Science
on the other hand if he carried it 500 m UP, then 100 * 500 = 50,000 Joules The problem does not say direction so who knows?
November 17, 2016

MATH HELP!!
Starlight Tree Farm sells Douglas firs and Noble firs. One December they sold 139 more Douglas firs than Noble firs. The total number of trees sold was 377. Which equation could be used to solve for n, the number of Noble fir trees sold
November 17, 2016

MATH HELP!!
You are welome
November 17, 2016

MATH HELP!!
25 6/25 - 20/25 = -14/25
November 17, 2016

math
100 times the fraction
November 17, 2016

US History
I guess maybe because Fort Neccessity is near Pittsburgh?
November 17, 2016

Calculus
delta x = .1 x range ____ y at right 1.0 to 1.1 ____ 2/1.1 = 1.82 times .1 = .182 1.1 to 1.2 ____ 2/1.2 = 1.67 times .1 = .167 1.2 to 1.3 etc in the end add them up .182 + .167 etc
November 17, 2016

US History
I do not think slaves were in Rhode Island before about 1700 so I agree with you. Pilgrims landed in Plymouth MA in 1620 and settlement of RI was thus later than that. I have my doubts about timing in SC as well.
November 17, 2016

physics typo?
Vi = 47 m/s d = 50 =============== v = Vi + a t 0 = 47 + a t a t = -47 or a = -47/t =============== d = Vi t + .5 a t^2 50 = 47 t + .5 a t^2 50 = 47 t +.5(-47/t)t^2 50 = 47 t - .5*47 t 50 = .5*47 t t = 100/47 then a = -47/(100/47)= -22 m/s^2 > twice gravity I think maybe ...
November 17, 2016

Math
13 = .65 x x = 13/.65 = 20
November 17, 2016

Math
(1/3)/5 = 1/15 but 5/(1/3) = 15
November 17, 2016

US History
The Spanish certainly DID find gold. They became the most powerful country in Europe for a while due to their riches from the New World. So I agree with you.
November 17, 2016

Math algebra
I have a hunch you mean f(x)= (x-2)/(x^2-81) which is (x-2)/ [ (x-9)(x+9) ] it is zero if the numerator is zero so when x = 2 it is undefined when the denominator is zero x = 9 or x = -9
November 17, 2016

Math algebra
AVA + .2*10^9 = 2 * AVE T + .6*10^9 = AVA AVA + AVE + T = 6.5*10^9 ============================ do them all in billions well T = AVA - .6 AVE = .5 AVA + .2 so AVA + .5 AVA + .2 + AVA - .6 = 6.5 2.5 AVA = 6.9 take it from there
November 17, 2016

Math algebra
(20+2x)(30+2x) = 936 600 + 100 x + 4 x^2 = 936 4 x^2 + 100 x - 336 = 0 x^2 + 25 x - 84 = 0 (x - 3 )(x + 28) = 0 x = 3 feet
November 17, 2016

ANOTHER TRIANGLE MATH PROB!
Get it?
November 17, 2016

ANOTHER TRIANGLE MATH PROB!
I said 12, and 12 is an option
November 17, 2016

ANOTHER TRIANGLE MATH PROB!
Now maybe you need to do this a more official way to really get it 21/24 = 10.5/x we want to get the 24 and the x out of the bottom so multiply both sides by 24 x 24 x (21/24) = 24 x (10.5/x) 21 x = 24 * 10.5 x = 24 * (10.5/21) x = 24 * (.5) x = 12
November 17, 2016

ANOTHER TRIANGLE MATH PROB!
21/24 = 10.5/x well 10.5 is half of 21 and we all know 12 is half of 24 so 10.5/12
November 17, 2016

Physics === Not hard
(1/2) k x^2 = (1/2) m v^2 k (.07)^2 = .0055 (11.4)^2
November 17, 2016

physics
Ke = (1/2) m v^2 = .5*.00335 * 255^2 in Joules = mass * heat of fusion of water = 3.35 * 333 J/gram
November 17, 2016

Math (equation of tangent line)
That is the second strange tangent line problem today. The first one was horizontal :)
November 17, 2016

re: Differential Calculus
Just copy your function into there: x^2cos^2y - siny = 0 look at the solution close to (0,0)
November 17, 2016

re: Differential Calculus
I mean parallel to x axis and y = pi for part 2, normal is up the y axis see http://www.wolframalpha.com/widgets/view.jsp?id=91851988c40ebbe236f5561e167c9ab8
November 17, 2016

Math
You are welcome.
November 17, 2016

Math
sqrt 15 = 3.873 3.873 * 10 = 38.73 which is about 39 so yes
November 17, 2016

TRIANGLE HELP!!!! (MATH!)
3/4 = 6/8 = 9/12 = 12/16 = 15/20
November 17, 2016

math
74 + 12*52 = 74 +624 = 698
November 17, 2016

Tod
Cool !
November 17, 2016

math
7/12 blue (12-7)/12 = 5/12 red
November 16, 2016

Math
(1/3) n = 5 n = 3*5 = 15 nights
November 16, 2016

Math
1.06 * 20.00 = 21.20
November 16, 2016

Arithmetic
3 for .20 is 12 for .80 so profit of .80-.70 = .10 dollars/dozen so .60 = 60 cents for 6 dozen
November 16, 2016

Physics
eff = Q/W = T2/(T1-T2) T2 = 26 + 273 T1-T2 = 33-26 = 7 eff = 299/7 = 42.7
November 16, 2016

Physics
gain in potential = m g h = 65 * 9.81 * 1100 Joules eff = ..25 so .25 energy = 65* 9.81 * 1100 so energy expended = 4*65*9.81*1100 Joules 4184 Joules = 1000 calories so in Calories (4/4.184)65*9.81*1100 power = energy expended/ time in watts = 4*65*9.81*1100/(37.5*60)
November 16, 2016

Math
1 2 3 4 5 6 first die 1 1 1 1 1 1 second die 2 2 2 2 2 2 3 3 3 3 3 3 4 4 4 4 4 4 5 5 5 5 5 5 6 6 6 6 6 6 total of 36 possibles the number one shows up 11 times 36 -11 = 25 times no ones 11/36 -25/36 = - 14/36 = -7/18
November 16, 2016

not linear
3495 *.8^t .8^5 = .328 or about $1150 which is not nothing but is also not much
November 16, 2016

Algebra
maybe: same as the probability that one of the numbers you choose is zero probability that first one is zero = 1/6 probability that second one is zero also is 1/6 so sum is 2/6 = 1/3
November 16, 2016

CHEMISTRY
try Gooling: ETHYLENE GLYCOL or antifreeze :) suspect it is Ethane-1,2-diol
November 16, 2016

Calculus
do the integral 4(x^2+1) dx/x^2and divide by the span which is 3-1 = 2 4 x^2 dx/x^2 + 4 dx/x^2 is 4 x - 4/x = 4 (x-1/x) at 3 = 4(3-1/3) = 32/3 at 1 = 0 so 32/3 divide by 2 16/3
November 16, 2016

American government
Well, if you just want my opinion as an uninvolved friend of the student, yes.
November 16, 2016

American government
I hope not. Read: http://www.google.com/search?q=amicus+curiae&ie=utf-8&oe=utf-8
November 16, 2016

american government
http://www.jiskha.com/display.cgi?id=1479316937#1479316937.1479317141
November 16, 2016

Dynamics
Vi = 80,000 m/3600 s a = -3.24 v = Vi + a t 0 = 80/3.6 - 3.24 t d = Vi t + (1/2) a t^2 = (80/3.6) t - 1.62 t^2
November 16, 2016

Calculus
(4/3)(x+3)^(1/3) but 0^(1/3) = 0 so right, zero
November 16, 2016

Math
x = xi - 5 y = yi + 7
November 16, 2016

math
b-s = 15 3 b = 8 s so b = 8s/3 8s/3 - 3s/3 = 15 5 s/3 = 15 s/3 = 3 s = 9 b = 9+15 = 24
November 16, 2016

maths
200 + 200 + 300 + 300 :)
November 16, 2016

Science
.01 * 6*10^23 * electrons per ion Do you really mean total electrons or valence electrons? If the latter it is two.
November 16, 2016

math
1.25^n = 2 n log 1.25 = log 2 n = log 2/ log 1.25
November 16, 2016

Math
(3*60/2) minutes /(1/5)minutes/pancake = 15 *30 = 450 pancakes and I do not believe you cook 5 pancakes per minute
November 16, 2016

math
360 = v t 360 = (v+10)(t-3) = vt -3v + 10t -30 so vt = vt -3v + 10 t - 30 10 t = 3 (v+10) but t = 360/v 3600/v = 3 v + 30 3 v^2 +30 v - 3600 = 0 v^2 + 10 v - 1200 = 0 v+40)(v-30) = 0 v = 30
November 16, 2016

math please explain!
You are welcome.
November 16, 2016

math please explain!
this is because in feet and seconds acceleration of gravity, g = 32 ft/s^2 then velocity v = Vi - g t where Vi is initial velocity and g = 32 ft/s^2 and height h is h = Hi + Vi t - (1/2)g t^2 in this problem h = Hi + Vi t - 16 t^2 where Hi = 20 and Vi = 120
November 16, 2016

math please explain!
h = 20 + 120 * 3 - 16 (9) = 20 + 360 - 144 in feet where g = 32 ft/s^2
November 16, 2016

The Maths
multiply second equation by -1 then add +4x + 3y = -2 -4x + 4y = 16 ---------------add 0 + 7 y = 14 so = +2
November 16, 2016

Math
diameter = twice the radius
November 16, 2016

Science
v = Vi + a t v = 10 + 2.5 t 40 = 10 + 2.5 t t = 30/2.5 x = vi t + (1/2) a t^2 = 10 t + 1.25 t^2
November 16, 2016

Maths
weight of dog at time t how much weight the dog gained between those times
November 16, 2016

Math
60/4 = 15
November 16, 2016

Calc
well the integral is x^4/4 + C Now in between x = 0 and x = 3 the slope of the integral must be f(0) = 0 f(3) = 27 so the integral must be between 0 + 0(3) = 0 or 0 + 27*3 = 81 In fact the integral is 3^4/4 = 81/4 or about 20
November 16, 2016

science
v = Vi + a t v = 0 + 2 (3.2) = 6.4 m/s
November 16, 2016

Math
(x+25)/2 = 3 x
November 15, 2016

Science
Flat , perpendicular hard walls, ceilings and floors are a no-no. Use heavy carpets, hanging heavy fabric, and soft ceiling tile. Break up the flat perpendicular surfaces with nooks and crannies and odd angles and big furniture. Use soft seating in an auditorium. You can get ...
November 15, 2016

Chem
.065 = .15 x + .01 .15 x = .055 x = 5.5/15
November 15, 2016

geography
I am inclined to say Google it but you get a barrage of propaganda. With the Balfour Declaration the English opened the eastern coast of the Mediterranean Sea to settlement by Jewish immigrants. That was kind of them but ignored the fact that people, namely Palestinians, ...
November 15, 2016

Algebra2
You are welcome.
November 15, 2016

Algebra2
(x+1)(x-3)(x-3) = 0 Three real roots single real at x = -1 double real at x = 3 http://www.wolframalpha.com/input/?i=solve+x%5E3+-5x%5E2+%2B+3x+%2B+9+%3D+0+%3D+0
November 15, 2016

algebra
one worker paints 400 meters in 5 hours so one worker does 80 meters/hour 80 m/wh * 4 w * 2 h = 640 m
November 15, 2016

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