Wednesday
July 23, 2014

Posts by Damon


Total # Posts: 17,491

CALC 2
1 at start a eats 2/3 ** 1/9 *** 1/54 b eats 1/6 ** 1/36 ** 1/108 first line is geometric series 2/3 + 2/3(1/6) + (2/3)(1/6)^2 ... An = 2/3 +(1/6)^n-1 sum of that series = a/(1-r) = (2/3)/(1-1/6) = 2/3 /5/6 = 4/5

Physics
You understand that he used quite different numbers in his example, D = 2.71 diameter 24 liters instead of 25 1.1 instead of 1.4 min

Physics
I found it all right. He has a pretty convoluted way of explaining it but it is the same thing. I have no idea why he converted to cm^3 rather than to meters^3 from Liters 1000 Liters = 1 m^3 1 Liter = 1000 cm^3 1 m^3 = 1,000,000 cm^3 but it is standard to work in meters, kg a...

Statistic
You are welcome :)

Statistic
p(good) = .7 , p(fail) = .3 n = 10 crunch it out with your binomial distribution P(2) for example = C(10,2)*.7^2*.3^8 = 10!/[8!*2!] * .49 * 6.56*10^-5 = 45 * .49 * 6.56*10^-5 = .001447

physics
work done = change in Ke = (1/2) m v^2 = 500*900 Joules power = work/time = 500 * 900 / 5 = 90,000 Watts

math
2 * 3 = 3 * 2 ????? Commutative

Calculus Help Please
f(x) = f(a) + (x-a) f'(a) f(x) = x^4 df/dx = 4x^3 let a = 2 then f(a) = 2^4 = 16 f'(a) = 4*8 = 32 f(x) = 16 + (x-a)(32) x-a = - .001 so f(1.999) = 16 -.001(32) = 16 - .032 f(1.999) = 15.968 with calculator it is 15.968 also

Math (check answer)
if you mean absolute value of 7 yes it is 7

Calculus Help Please!!!
at x = 3 y = 3*3 - 9 = 0 at x = 2.4 y = 3(2.4) - 2.4^2 = 1.44 delta y = 1.44 -0 = 1.44 dy/dx = 3 - 2 x at x = 3 dy/dx = 3 - 6 = -3 if dx = -.6 dy = -3 (-.6) = 1.8

Algebra
.163 x = 47600 x = 47600/.163

Math
You are welcome :)

Math C redone
should subtract 30 (14*2+2), not 44 c) draw a Venn diagram Only in A1 = 103 - 30 = 73 Only in A2 = 992- 30= 962 Only in A3 = 10011 - 30 = 9981 shared = 3*14 + 2 = 44 sum = 11060

Math
a) just add them 11106 b) They are all in A3 so 10011 c) draw a Venn diagram Only in A1 = 103 - 44 = 59 Only in A2 = 992- 44= 948 Only in A3 = 10011 - 44 = 9967 shared = 3*14 + 2 = 44 sum = 11018

Math
do you mean y = 18/(x^2-9) ???? if so dy/dx = -18 (2x)/(x^2-9)^2 0 at x = 0 In that interval the bigger |x|. the more negative the function so it is max when x = 0 18/-9 = -2 so C

math
You are welcome, good luck.

math
25 * .65 = 16.25 25 * 0.65 * 0.2 = 3.25 but I do not believe that 0.2. I think you have the loss 80% when it should be like 20%

math
the cooking loss is 80% ??? that does not sound right but if you are serious then 25 * (1-.35) (.2)= 25*.65*.2 = 3.25 pounds

Algebra
x^2 + (2x+20)^2 = (2x+22)^2 x^2+ 4 x^2 + 80 x + 400 = 4 x^2+88x + 484 x^2 - 8 x - 84 = 0 (x-14)(x+6) = 0 x = 14 2x+20 = 48 2x+22 = 50

physic
Plus charges flow to one side, minus charges to the other.

Calculus Help Please!!!
Oh, I see f(x) = ln (1+x) df/dx = 1/(1+x) d^2f/dx^2 = -1/(1+x)^2 f(x) = f(0) + [1/(1+0)] x - x^2/2! ... f(x) = 0 + x - x^2/2 + ..... well at a first cut when is x^2/2 =.1 x? x/2 = .1 x = .2

Incomplete!
Linear approximation to what function? Did you try to copy and paste? If so, that does not work here.

Physic
zero The plus charges on one side exactly balance the - charges on the other side. If you for example had more plus charges on one plate then they would attract negative charges to the opposite plate and would cause a flow across. Moreover the entire capacitor would then have ...

Science
I do not understand what the second question means? Balance the equations or what?

Science
Al is +3 here 2 Al + 2CuCl2 --> 2AlCl3 + 3Cu

Math
look for where second derivative is positive. ( x <0.75) https://www.wolframalpha.com/input/?i=second+derivative+of+-1%2F%28x-.75%29

Physical Science 9
Incomplete combustion ---> carbon particles and CO instead of CO2 That is not a good question by the way. You should know that for sure. The other things happen in: plants stomachs compost heaps and coffins not power plants

Physics 112
a) as t--> oo inductor is a short circuit, no reactance so V = i at big t * R V = (8.4)(.26) = 2.14 Volts b) at t = 0, i = 0, so all voltage across L 2.14 = L di/dt let i = 8.4 [ 1 - e^-t/tau ] given tau = .1 s i = 8.4 [ 1 - e^-10 t ] di/dt = 8.4 (10 e^-10 t) di/dt = 84 at ...

Math
1cm /50 in = 4 cm/x in x = 200 in

Math
It is not a proportion. It is a fraction. divide 144 by 1200 get .12 to convert a fraction to a percent, multiply by 100 100 * .12 = 12 %

Math
12/8 = 3/2 = boys/girls boys/total = 3/5 girls/total = 2/5 so that boys/girls = 3/2 so girls /total = 2/5 = girls/400 girls = 800/5 = 160

Physics
You are welcome :) Good luck. Come back and tell me when you find out.

Physics
I know the flow rate is the speed times the area. That is my field :)

Physics
I can not find an error. I hope one of the other math/physics teachers finds something.

Physics
call 41.18 41.2 maybe, sometimes they fuss about their round off rules.

Physics
Well, it is their word against mine I guess, but check my arithmetic and units carefully Physics - Damon, Sunday, March 30, 2014 at 7:21pm 25 L = 25 * 10^-3 m^3 2.77 cm = .0277 m 1.4 min = 84 seconds flow rate * time = amount pi r^2 v * 84 = .025 m^3 pi (.0139)^2 v = .025 v = ...

Steve, Reiny ??
I did this twice and do not see errors. Did I make some stupid mistake?

Physics
Well, figure out what I did wrong. (I think nothing)

This is getting tiresome
I answered this. Also the other one about circumferences several times.

Math
1/2 if a length dimension on the big one is twice the same length dimension on the little one then lengths on the small one are 1/2 those on the big one.

Math
4 * 50

Math
4 n - 6 = 2 n + 4 2 n = 10 n =5

math
22.5 quarts = .75 (total) total = 22.5/.75 we have .25 * total so we have .25 * 22.5/.75 =22.5/3 = 7.5

Physics
25 L = 25 * 10^-3 m^3 2.77 cm = .0277 m 1.4 min = 84 seconds flow rate * time = amount pi r^2 v * 84 = .025 m^3 pi (.0139)^2 v = .025 v = 41.18 m/s if 1/3 diameter then 1/9 of area so speed is nine times original 371 m/s

Physic
http://www.jiskha.com/display.cgi?id=1396215852

Physic
I did my best earlier.

Calculus Help Please!!!
LOL - Guess which of us is the mathematician and which is the Engineer :)

Calculus Help Please!!!
Q = incoming flow rate = .1 m^3/min dh/ dt = Q A where A = surface area = length * width at 20 cm depth which depth is (1/2) height width = 30 + 1/2(70-30) = 30+20 = 50 cm = .5 m wide water surface so A = 5 * .50 =2.5 m^3 so finally dh/dt = .1 * 2.5 = .25 m/min = 25 cm/min

Physics
vertical ? I thought table was level. I will assume you mean from the y axis. final momentum y component = m (5) cos 28 + m (4) cos 32 = 7.81 m final momentum x component (I will assume one + and the other -) = m (5) sin 28 - m(4) sin 32 = 2.18 m Now I will have to assume some...

Physics
inelastic, energy was radiated in sound waves

Physics
If Vector A + Vector B = Vector C then orthogonal components of the vectors also add. If V = A + B then Vx = Ax + Bx and Vy = Ay + By and Vz = Az + Bz and as many more dimensions as our tensor occupies ") (b) NO !!!!! It is only conserved in an elastic collision Energy is...

algreba
In both cases just add the two equations

My typo
" Libel is viewed differently in United Staes and Japanese law and is far more difficult to establish in a United States court. "

Proofreading..Jrn Law
Should it not say in an introductory sentence that you are talking about libel? Such as: " Libel is viewed differently in United Staes and Japanese law and is far more difficult to establish in a Japanese court. " win THE case or HIS OR HER case (singular or say &quo...

physic
Use the same argument but same voltage on each

physic
In series the charge has to be the same on both, call it Q by definition each capacitance C= Q/V so Veach = Q/C now in series the voltages on each capacitor add so V total = 2 Q/C but by definition our equivalent capacitance = Q/Vtotal = C/2

whoops
Use Steve's answer

math
makes good 2 miles per day after 12 day/night cycles is at the 24 mile mark so he will just make it at dusk on the 25 th day

physics
BUT they want miles/ hr so 29.4 m/s * 1 mile/1609 m * 3600 s/h = 65.8 miles/hour

physics
the ground is 3 seconds down d = (1/2) (9.81) (3)^2 correct d = 44.1 METERS (THAT IS PART B) (that is 9.81 m/s^2 * 9 s^2 so just m or meters) NOW THE SPEED (Part A) v = g t v = 9.81 m/s^2 * 3 s = 29.4 m/s (THAT IS PART A)

physics
You are terrribly fouled up with units. Give me a minute

physics
WORK IN METRIC convert later if dealing with carpenters.

physics
come on now, use what we have done v = g t but to go from m/s to mi/hr use 3600 seconds / hour and 1609 meters/mile a floor is about 3 meters

Math
2 = 1.0275^n log 2 = n log 1.0275 n = 25.6 years

statistics
Binomial distribution find probability of zero boys P(0) answer is 1 - P(0) n = 6 p = .5 and 1-p = .5 P(0) = C(6,0) (.5)^0 (.5^6) coef for any n,0 = 1 so P(0) = .5^6 = .0156 1-P(0) = .984

Math 110 UOP
Multiply 28x72 using lattice method. been there done that, see below and please post once HUH, 5^2 = 4^2 +3^2 if that is what you mean

Math 110
278 = 2*139 139 is a prime number to that is the end ***** 2 ***** 8 **** 1->2 1/4 **** 5/6 ** 7 9->0 0/4 **** 1/6 ** 2 11->1 *** 6 so 2016

physics
What speed does the ball in the first question have in falling 3.5 s? ------------------- I told you in the first line, 34.3 m/s ------------------- in 4 sec d = .5 * 9.81 *16 = 78.5 meters so no

physics
v = g t = 9.81 * 3.5 = 34.3 m/s but what if it hit the ground? d = (1/2) g t^2 = 60 meters so it has not hit ground yet, whew

Physics
area = A = pi D^2/4 = pi (.0277^2)/4 = 6.03*10^-4 m^2 Q = volume/second 25 * 10^-3 m^3 / 84 s = .298 *10^-3 m^3/s A v = Q v = Q/A = .298*10^-3/6.03*10^-4 = .0494 *10^1 = .494 m/s

physics
a = change in velocity/change in time = 44/5 = 8.8 ft/s^2 a = same formula = (88-44)/4 = 11 ft/s^2 a = (66 -88)/3 = -7.33 ft/s^2 sum of a*t / total t (8.8*5 + 11*4 - 7.33*3)/12 = 5.5 m/s^2

physics
5/20=4 km/min = 4,000 m/min = 66.67 m/s? BECAUSE 5/20 = 1/4 not 4

physics
5000 meters in 20*60 = 1200 seconds Vi = 30,000 m / 3600 s = 83.3 m/s v = Vi + a t 0 = 83.3 + a (1200) a = - .0694 = - 6.94 * 10^-2 m/s^2 average velocity with constant acceleration = (first + last)/2 = 83.3/2 = 41.7 m/s

physics
750 m/ 20 s 1500 m / 45 s

college algebra
2 x 10to the what? and 3.5 times ten to the what ?

US government
Well, presidents seem to start wars without much voting in Congress these days :)

US government
Well, I guess our first choices are consistent :)

US government
the government the citizens among many other possible answers such as: money, health military, poor capital , labor federal government , states

Math
a = .5 r = .5 a r^(n-1) = .5 * .5(6) = .0078125 That is maybe a pepper corn :) http://www.mathsisfun.com/algebra/sequences-sums-geometric.html

math
Yes, I wondered about this state's educational achievements as well :)

math
.56 (11) = 6.16 I have no idea what the standard deviation is so can not do more. If I knew it I would use mean of 6.16 and some standard deviation in: http://davidmlane.com/hyperstat/z_table.html

Physics
The force from the car on the truck = 4420 - 1230 a So our task is to find a total m = 1230 + 2180 = 3410 kg total F = 4420 - 750 = 3670 N so a = 3670/3410 = 1.08 m/s^2 so finally F on truck = 4420 - 1230 (1.08) F on truck = 3096 Newtons

calcules
change in percent bought is only half the percent change in price

calcules
Q = 342.5 / P^.5314 dQ/dP = -342.5 (.5314) P^-.4686/ P^1.063 so dQ/dP = - 182 P^-1.5316 well, we need to know what P is at the intersection P = q P^1.5314 = 342.5 1.5314 log P = 2.535 log P = 1.655 P = 45.2 so dQ/dP at intersection = -182(45.2)^-1.5316 = .531

probability
Steve answered this above.

physics
The electric company is supplying energy to the room and it is heating up. We hope she is using a CFL or LED lamp to minimize heating of the room and waste of energy.

3 science questions
7. Which of the following is used to make biomass fuel? B. plants and animal waste C. coal <----- ============================ NO !!!!!!!!!! plants and animal waste!! bio mass means made out of present biological materials, not dinosaurs. ----------------------- 11. Solar, ...

physic
change in rpm = 170 170 rev/min *1 min/60 s * 2 pi radians/rev = 17.8 radians/second change which is delta omega alpha = change in omega/ change in time -17.8 radians/second / 4.4 seconds = 4.05 radians/second^2

no figure
You can not copy and paste here so I can not see the geometry.

Physic Angular momentum and torque
r = 0.19 m I =.5 m r^2 =.5 (1)(.19)^2 = .0181 kg m^2 1700 rev/min * 1 min/60 s * 2 pi rad/rev = 178 radians/second = omega L =I * omega .0181 * 178 = 3.22 kg m^2/s final omega = initial omega - alpha t alpha (4.6) = -178 alpha = - 38.7 radians/s^2 Torque = I alpha = -.0181 (38...

Physic Moment of inertia
I = (2/5) m r^2 = (2/5)(11.1)(.630) = 2.8 kg m^2

Help!! Physics
c = speed of light = 3 * 10^8 m/s 199 = c T T =199/3*10^8 f = 1/T = 300* 10^6/199 = 1.51 * 10^6 Hz omega = 2 pi f = 9.47 * 10^6 omega^2 = 1/(LC) = 89.7*10^12 so C (785 * 10^-6) = (1/89.7) 10^-12 C = (1/70414) 10^-6 = 1.42 * 10^-5*10^-6 = 1.42 * 10-11

algebra
It represents the average speed during that interval or in other words the distance traveled during that interval/ 3 seconds d(5) = 16 * 25 = 400 d(2) = 16*4 = 64 distance during those three seconds = 400-64 = 336 feet 336 ft/3 s = 112 ft/s = average speed for that interval By...

Stats
easy to say they do not happen 1-pA = .6 1-pB = .5 so probability that neither happens is .3 so probability that at least one happens is 1-.3 = .7

maths natural log
Huh ? as t--> oo e^-anything t ----> 1/ e^big ---->0 so W ---> 0 and b ---> 800 What happened was that the black increased form their initial 50 to their final 800 while destroying the white populations, typical invasive species.

Stats
http://davidmlane.com/hyperstat/z_table.html

Stats
I can not see your graph. You can not copy and paste here, but find the area in that region

math
1000 * .90 * .90 = ?

Calculus
the rate of change of volume is the surface area times the rate of change of height 450 ft^3/min = surface area * dh/dt surface area = pi r^2 450 = pi (30^2) dh/dt dh/dt = .159 ft/min You could do this by saying V = pi r^2 h dV/dh = pi r^2 dV/dh*dh/dt = pi r^2 dh/dt chain rule...

math
you mean how many zeros I think look at b^2-4ac 49 -16*8 is NEGATIVE so two complex conjugate solutions, NO real solutions

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