Monday
August 31, 2015

Posts by Damon


Total # Posts: 21,819

Plus
10* 569 = 5690 2 * 569 = 1138 add those 12* 569 = 6828
August 30, 2015

Math
10 * 20 * 500 = 200 * (1,000/2 ) = 100 * 1,000 = 100,000
August 30, 2015

Science - physics
average speed during stop = 122/2 = 61 m/s to get time to stop v = 0 = 122 - 6.2 t t = 122/6.2 = 19.7 seconds so distance = v average * t = 61*19.7 = 1200 meters Off the end of the runway and 200 meters into the bleak ocean
August 30, 2015

Calculus
f' = sec x tan x + 2 sin x at x = pi/3 which is 60 deg f' = m = (2 * sqrt 3) + 2 (sqrt 3/2) so m = 3 sqrt 3 so y = 3 sqrt 3 * x + b at (pi/3 , 1) 1 = 3 (pi/3) sqrt 3 + b b = 1 - pi sqrt 3 so y = (3 sqrt 3) x + (1-pi sqrt 3) or approx y = 5.20 x - 4.44
August 30, 2015

Calculus
nothing wrong with that
August 30, 2015

MATH ALGEBRA
x = number of trees at year n at year 0, x0 = 7000 at year 1, x1 =.88*X0 + 600 = 6160+600 = 6760 at year 2, x2 = .88*x1 +600 = 6548.8 at year 3 , x3 = .88x2+600 = 6362.9 at year 4, x4 = .88*x3 + 600 = 6199.4 at year 5, x5 = .88*x4+600 = 6055.5 at year 6, x6 = .88*x5+600 = 5928...
August 30, 2015

math calculus
typo in second line .7 = e^-40 k
August 30, 2015

math calculus
a = A e^-kt .3 = e^-40 k ln .7 = -.357 = -40 k k = .008917 so 1/2 = e^-.008917 t if t is half life ln .5 = - .693 = -.008917 t t = 77.7 hours
August 30, 2015

math
Been there, done that: http://www.jiskha.com/display.cgi?id=1440890314
August 30, 2015

Calculus
If this is y = [ x^4 + x ]^.5 ?????? dy/dx = .5 [ x^4 + x ]^-.5 (4x^3 +1) = .5 (4x^3+1) /sqrt(x^4+x) ================================= if you mean y =( x^.5 )(x^3+1) y = x^3.5 + x^.5 dy/dx = 3.5 x^2.5 + .5 x^.5 /x = x^.5 ( 7 x^2 + 1/x)/2 = x^.5 (7 x^3 + 1) /(2 x) = (7 x^3 + 1...
August 29, 2015

Physics
Bug dv/dt = ab = 60 mi/h/2.4s = 25 mi/(s h) = 40.2 km /(3600 s^2) Sal dv/dt = as = 60/2.8 = 21.4 mi/(s h) =34.4 km/3600s^2 v = 75 km/h = 75 km/3600s then v = a t or t = v/a Bug: t = 75 km/3600 s / 40.2 km/3600s^2 = 1.87 seconds d = (1/2) a t^2 = OR use half max (average) speed...
August 29, 2015

SCIENCE!
1. - Did the rock chip hit him in the eye? 2. what mistake did Andrew make using measurement units? for density he needs VOLUME, not distance. He measured centimeters. He needs centimeters CUBED or cm^3 or cc 3. yes, write it in your lab notebook ! 4. I think he determined the...
August 29, 2015

math
I will try to reverse engineer what you are doing because I am not sure I understand you Say we are doing a compound interest problem. Yearly interest rate as a decimal is r For example 5% is .05 then every year I multiply what I have is the amount from the year before + r ...
August 29, 2015

Math
s^2 + 1 = (1/2)(4s) s^2 - 2 s + 1 = 0 (s-1)(s-1) = 0 s = 1
August 29, 2015

math
for exponential growth (continuous compounding) amount = original * e^rt rate = -.02 or -2 percent for example if you have ten dollars then after one year you will have 10 e^-.02 = 10(.980298) = nine dollars and eighty cents so each year multiply by .98 NOT 1.98 BUT that is an...
August 29, 2015

Geometry
5p^2-23p+24 well 24 = 4*6 or 3*8 or 2*12 or 1*24 so what might work in ( 5 p - %%) (p - %%) 15 and 8 is 23 so try 3*5 and 8 (5 p - 8)( p - 3 )
August 29, 2015

math
r = 0.06 meters A = pi r^2 F = 350,000 Newtons p = F/A = 350,000 /(pi *.06^2) in Newtons per square meter which is Pascals
August 29, 2015

pre-calculus
1) if it is really 4x = 3 then x = 3/4 a vertical line 2) 9y - 7 - 3y = 0 6 y = 7 y = 7/6 a horizontal line of slope 0 3) 7 x + 2 y = 14 2 y - -7 x + 14 y = -(7/2) x + 7
August 29, 2015

integral calculus
hmmm, graph that first function. sin a cos b = (1/2)sin(a+b)+(1/2) sin(a-b) (remember about beat frequencies :) so (1/2)[ sin(5x) dx - sin(x) dx ] ok? ======================================= let y = 3x then dy = 3 dx or dx = (1/3) dy so (5/3) [ cos^2 y dy ]
August 29, 2015

Science
agree
August 29, 2015

Physics
m = F/a
August 29, 2015

Physics
2*3600 seconds/h = 7200 seconds 75 * 7200 = 540,000 Joules total electricity use .7 * 540,000 = heat Joules .3 * 540,000 = light Joules
August 29, 2015

Math
x y = 15876 y = 9 x so 9 x^2 = 15876 x^2 = 1764 x = 42 =================== 169 + x^2 = 794 x^2 = 625 x = 25
August 29, 2015

Chemistry
150.01 - 104.70 = 45.31 grams of syrup .140 pint = 66.2 mL true so density = 45.31 grams/66.2 mL = 0.684 grams/mL = 0.684 grams/cubic centimeter
August 29, 2015

physics
work done on metal = m g h = .411*9.81*5.22 = 21.05 Joules 21.05 = .344 ke of hammer so ke of hammer = 61.2 Joulesd (1/2) 8.46 v^2 = 61.2 v^2 = 14.5 v = 3.80 m/s
August 29, 2015

physics
find bullet momentum from conservation of momentum .05 v = .55 * 4 = 2.2 then 2 V + 2.2 = 0 V = -2.2/2
August 28, 2015

physics
1.5*10^-4 = (1/2) (2.4*10^-4) v^2 so v^2 = 3/2.4 = 1.25 v = 1.11 m/s
August 28, 2015

physics
at takeoff Ke = (1/2) m v^2 = 1.5*10^-4 solve that for v work done = force * distance 1.5*10^-4 = .42 * distance
August 28, 2015

physics
change in potential energy = m g h the gravitation force is opposite to the direction of motion so work done = -m g h the escalator force is in the direction of motion so work done by it is +m g h
August 28, 2015

physics
Q = flow rate = speed * area 43 pi R^2 = n * .066 pi r^2
August 28, 2015

physics
delta p = rho g delta h 35*10^3 = 1025 *9.81 * h h = 3.48 meters
August 28, 2015

physics
hey, I did the one about the eardrums.
August 28, 2015

physics
k x = 250 = 510 x so x = 250/510
August 28, 2015

physics
power = work/time = F * d /t so 50.2 = F * 1.17 / 1.84 = 78.9 N agree
August 28, 2015

Physics
v = a t
August 28, 2015

Idk
tow means two? 2.5/3 = .8333333333333333333333333333
August 27, 2015

Geometry
Draw it 5x-3 + x-9 = 5 x -12 + x = 0 x = 12 HJ = 5(12)-3 = 57 JK = x-9 = 3
August 27, 2015

Math
Look 8^1 = 8 8^2 = 8*8 = 64 8^3 = 8*8*8 = 64 * 8 = 512 8^4 = 8*8*8*8 = 512 * 8 = 4096 8^5 = 4096*8 = 32768
August 27, 2015

Math
8*8 = 64 64*8 = 512
August 27, 2015

Algebra
76-12 = 64 for n = 2 108-76 = 32 for n = 3 124 -108 = 16 132 - 124 = 8 136 - 132 = 4 138 - 136 = 2 139 -138 = 1 139.5- 139 = .5 Yn+1 - Yn = 64/2^(n-1) or Y1 = 12 Yn+1 = Yn + 64/2^(n+1)
August 27, 2015

Physics
V = pi (5)^2 * 15 m/V = 1.3 so in grams m = 1.3 V divide by 1000 to get kg
August 27, 2015

Geometry check
You are welcome.
August 27, 2015

Geometry check
You are not stuck, you are doing fine. Yes (1/2) * (1/2) = 1/4 :)
August 27, 2015

Geometry check
Yes, I agree with you.
August 27, 2015

math
.8*7.95 = $ 6.36
August 27, 2015

Equation
x^2 - b x + (b - 1) = 0 x = [ b +/- sqrt (b^2 - 4b+4 ) ]/2
August 27, 2015

Computer
Word is a software program.
August 27, 2015

Math
An infinite number of them. What are your choices?
August 26, 2015

Algebra
20.00 - 3.00 x
August 25, 2015

College Physics
get t from v = a t then get d from d = (1/2) a t^2
August 25, 2015

Math
You do not even need the trig formulas for this because if sin A = .5 then in the first quadrant A = 30 degrees so 2A = 60 degrees cos 60 = 1/2 sin 60 = (1/2)sqrt 3
August 24, 2015

math
let u = 1/x let v = 1/y 5 3 |u| 19 2 1 |v| 7 D = 5*1-3*2 = 5-6 = -1 Du = 19*1-3*7 = 19-21 = -2 Dv = 5*7-19*2 = 35-38 = -3 then u = Du/D = -2/-1 = 2 so x = 1/u = 1/2 and v = Dv/D = -3/-1 = 3 so y = 1/3 You have typos I think I assume the second one is actually log x + 2 log y...
August 23, 2015

Math typo I think
7,361,920,000 * 1.0114
August 23, 2015

calculus
assume n is constant in general: d/dx a^u = a^u * ln a * du/dx so dy/dx = 2^nx * ln 2 * n
August 23, 2015

alGEBRA 1
12 *1.03 = 12.36 highest 12 * .97 = 11.64 lowest -------------------------subtract range = .72 from lowest to highest
August 23, 2015

Economics
if your currency is weak, travel to a strong currency place becomes expensive. weak rand and strong dollar ----> fewer dollars per rand which means more rands per cup of coffee in New York.
August 23, 2015

Calculus
f+dx = 2(x+dx) - 5 = 2 x + 2 dx -5 f(x) = 2 x - 5 ((f(x+dx) - f(x)) = 2 dx divide by dx = 2 no need to approach 0 with this, the slope of a straight line is constant. by the way the derivative of 2 x - 5 is 2
August 23, 2015

Math
37 - 19 if all in a row.
August 22, 2015

statistics
http://davidmlane.com/hyperstat/z_table.html
August 22, 2015

physics
v = a t
August 22, 2015

physics
since the was no change in direction, the speed is the magnitude of the velocity with no directions specified. ( poor wording of question, velocity is a vector with magnitude and DIRECTION. Speed is just a scalar. For speed use a speedometer. For velocity you need the ...
August 21, 2015

physics
figure out how long the whole trip took t = 11.2/52 + 23.2/40 + 48.2/31.9 and how many miles total? d = 11.2 + 23.2 + 48.2 then average speed = d/t
August 21, 2015

Geometry
difference in x = (7-1) = 6 difference in y = (-7 -1) = -8 hypotenuse = distance = sqrt(36+64) = 10
August 21, 2015

Algebra
x^5/2 * x^-3/2 = x^1 = x 5^-1/2 * 5^1 * 5^-3/2 = 5^-1 =1/5 x/5
August 21, 2015

Dimensional Analysis Chemistry
You are welcome :)
August 19, 2015

Dimensional Analysis Chemistry
ppm = M * molar mass * 1,000 = 2.1*10^-9 * 207.2 * 10^3 = 435*10^-6 = 4.35 * 10^-4 ppm Agree with you however would there not be more parts per billion than parts per million? 1 ppm = 10^3 ppb so 4.35 * 10^-1 ppb
August 19, 2015

Calculus
do you know that sin x ---> x as x --->0 ? if not I will show below given that sin x --> x we have 3x/x = 3 ===================== series for sin x sin x = x - x^3/3! + x^5/5! .... as x --0 sin x --> x - much smaller stuff
August 19, 2015

Algebra 2
this is an arithmetic series with a = 500 d = 10 look at https://www.mathsisfun.com/algebra/sequences-sums-arithmetic.html
August 19, 2015

algebra
33
August 19, 2015

Math
A2 = 180 - A1 A2 = 180 - 115 = 65 because they are supplements 90 - 65 = 25 because complements add to 90 degrees
August 19, 2015

math
You are welcome :)
August 19, 2015

math
put a line through A and B slope = 9/3 = 3 2 = 3 (0) + b y = 3 x + 2 now c 15 = 3*5+2 no, oh dear then D 23 = 3*7 + 2 yes and E 3x+2 = 3 x + 2 yes So C is no good, invalid, evil, boil in oil
August 19, 2015

G ss jikowyi subject physics
Thank you Lori. That saves me some time.
August 19, 2015

Social studies.
Probably A is correct.
August 18, 2015

MATH
12*4/5 = 12/1 * 4/5 = 12*4 / 1*5 = 48/5 = 9 3/5
August 18, 2015

physics
pressure * one tire area = (717+80)/2
August 16, 2015

Physical science
Sorry, ball E both has no charge and a positive charge. I can not make sense of this or I would have replied long ago. It is either as typo or an error or I am simply not understanding. if the rod attracts E , E is + B is - so D is + so D would repel E Repel and no effect is a...
August 15, 2015

Urgent math
look up binomial expansion (p+q)^n = p^n + C(n,1) p^(n-1)q^1 ... etc where c(n,m) = n!/[(n-m)! m!] for n = 5 the coefs are 1 5 10 10 5 1 so 32x^5 + 5*16x^4*y^2 ...... y^10
August 15, 2015

pre-calculus urgent
a(n) = a(n-1)r [a(n)]^2 = [a(n-1)r]^2 = [a(n-1)]^2 r^2 so common ratio is r^2 instead of r
August 15, 2015

pre-calculus urgent
a(n) = a(1) + (n-1) d a(10) = 2 = 6 + 9 d -4 = 9 d d = -4/9
August 15, 2015

Math
first term = 1/3 term(n+1) = (2/3) term(n) geometric sequence with a = 1/3 and r = 2/3 look here: http://www.mathsisfun.com/algebra/sequences-sums-geometric.html
August 15, 2015

Algebra 1
This makes little sense but anyway: c^2 - 10 c + 16 = - p c^2 - 10 c = - p - 16 c^2 - 10 c + 25 = -p + 9 (c-5)^2 = - (p-9) max at c = 5 and p = 9
August 14, 2015

Physics
20^3 = 2^3 * 10^3 = 8,000 6.5 g/cm^3 * 8,000 cm^3 = 52,000grams = 52 Kg 1300g * (1 cm^3/6.5g) = 200 cm^3
August 14, 2015

Pre-Calculus
3000 = 675 + .11 (s-1900) 2325 = .11 s - 209 .11 s = 2534 s = 23036.36
August 14, 2015

afrikaans (AFK503/101)
niets te danke :)
August 12, 2015

afrikaans (AFK503/101)
Oh my: I see the following: 11.5.4 Afrikaans is nie my moedertaal nie. Mag ek die werkopdragte en die eksamenvraestel inEngels beantwoord? AFK1053 is ‘n module wat gemik is op die verbetering van studente se Afrikaanse taalvaardighedeten opsigte van lees, luister, ...
August 12, 2015

afrikaans (AFK503/101)
Kommunikasiegapings = gaps in communication flaaitaal = street talk (Vlaai is a baked good in the Netherlands)
August 12, 2015

Mathematical Economics and Linear Programming
[ bottom d top/dx - top d bottom/dx]/bottom^2 [(cx+d)(2ax) - (ax^2+b)(c)] /(cx+d)^2 agree = [2acx^2+2adx - acx^2-bc] /(cx+d)^2 disagree sign of bc = [acx^2 + 2adx - bc ] /(cx+d)^2
August 12, 2015

Algebra ASAP
yes for n=1 3^2 -1 = 8 3^2(n+1) - 1 = 3^2n * 3^2 - 1 so 3^2(n+1) - 1 = 3^2n * 9 -1 = 3^2n * 8 + 3^2n-1 = 8 times something + the one before
August 12, 2015

Physical Science- Atomic Structure
What goes in comes out.
August 12, 2015

Physics
I think that is the altitude, not the radius. Use 26,199 mi
August 11, 2015

Physics
iniitial angular momentum about hinge = m v r = .010 *400 * 1 = 4 kg m^2/s or omega = v/r = 400/1 I = m r^2 = .010 (1)^2) so I omega = .01 * 400 = 4 agains now final angular momentum is the same I = .010 *1^2 + (1/3)(10)1^2 = .01 + 10/3 = 3.34 kg m^2 so I omega = 4 = 3.34 ...
August 11, 2015

Physics
I guess the moment or inertia is 1/3 of original If I w is constant then w' = 3 w then if original Ke = (1/2) I w^2 the final is (1/2)(I/3)(9w^2) = 3 times original has to do work to pull mass in toward the axis of rotation against centripetal force.
August 11, 2015

physics
specific r double ---> double r diameter doubles --> resistance 1/4 lenght * 3 ----> r *3 2/4*3 = 3/2 3/2 * 2 ohms = 3 ohms
August 11, 2015

calculus
Its slope is the same as of y = -6x+6 or slope = -6 at (1,0) so do it just like I did the other one.
August 10, 2015

calculus
d^2y/dx^2 = 6x - 6 dy/dx = 3x^2 - 6 x + c that is zero at x = 2 3*4 -6*2 + c = 0 c = 0 y = x^3 - 3 x^2 + k 1 = 8 - 12 + k k = 5 so y = x^3 - 3 x^2 +5
August 10, 2015

Math
pi is about 22/7 .25 * pi r^2 =22/(7 *4) = 22/28 = .79
August 10, 2015

Math
4+7 = 11 so for x 4/11 (0 - -33) + -33 = 12 +-33 = - 21 and for y 4/11(44-0) + 0 = 16 so (-21 , 16)
August 10, 2015

pre-calculus
same as ratio of circumferences 8 rpm = 8 * 2 pi radians/60 seconds
August 10, 2015

Math
at 5 seconds it has fallen 16 * 25 at 6 seconds it has fallen 16 * 36 so between 5 and 6 it falls 16(36-25)
August 10, 2015

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