Saturday
August 23, 2014

Posts by Damon


Total # Posts: 17,988

calculus help
try : https://www.google.com/search?q=graph+ln%28x%29+from+1+to+6&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a&channel=sb ln 6 = 1.79 ln 1 = 0 ln 6 - ln 1 = 1.79 1.79/5 = .36 approx ln x = .36 e^ln x = ? = e^.36 so x = 1.43 sure enough between 1 and 6 :)
April 16, 2014

Algebra
2 (a+1) / [(a+1)(a-1)] for starters :)
April 15, 2014

Geometry- trig ratio
sin 55 = 21,000/hypotenuse we want that hypotenuse
April 15, 2014

science
you want traction, not slipping, so increase friction.
April 15, 2014

Math
sin 10 = PR/16 PR = 16 sin 10
April 15, 2014

Algebra
You are welcome. You could have done this by long division but often you can see the factors more quickly.
April 15, 2014

Algebra
2 x^3 – x^2 – 24 x + 12) = (2 x^3 -24 x) - (x^2 - 12) = 2 x (x^2-12) - 1 (x^2-12) = (2x-1)(x^2-12) now divide that by (2x-1) :)
April 15, 2014

Math
sin 10 = PR/16 PR = 16 sin 10
April 15, 2014

Math
1.05^2 - 1 = 10.25 APY Wilder 1.0081666^12 - 1 = 10.2524 APY Cheapskate so go with cheapskate ten years 1.05^20 =2.6532 *85,000 = 225,530.30 1.0008166667^120 = 2.65387 *85,000 = 225,579.18 Cheapskate is 48.88 better
April 15, 2014

english
The magnificent king emerged victorious eliciting a groan from his opponent who had been deserted by his muses depriving him of the strength of his convictions :-)>
April 15, 2014

Geometry - Area
You are welcome :)
April 15, 2014

Geometry - Area
find the area of each of the 6 equilateral triangles making up the hexagon Each side of triangle = 12 yards { by the way, first check apothem length because it is our altitude ) tan 30 = (1/2)(12)/apothem apothem = 6/tan 30 = 10.4 - sure enough, whew } so area of triangle = (1...
April 15, 2014

math
5 * .011 * p = 82.5
April 15, 2014

math
10 * .025 * 5000 5000 + part A (ignoring inflation :)
April 15, 2014

chemistry
Use google for conversion 1500 mm Hg = 1.97368421 atm = 199 983.553 pascals
April 15, 2014

Algebra II
In other words you did one of 120 sequences that yield 7 successes out of 10 trials.
April 15, 2014

Algebra II
....but the probability of failure is not independent of the probability of success :)
April 15, 2014

Algebra II
binomial distribution p(sucess) = 12/15 = 4/5 = .8 1-p = 1/5 = .2 n = 10 k = 7 P(x=7) = C(10,7) * .8^7 * .2^3 C(10,7) = 10!/[ 7! (3!) ] = 10*9*8 / (3*2) = 80*9/6 = 120 so P = (120)(.8^7)(.2^3) = 0.201
April 15, 2014

geometry
100 = 4x^2 25 = x^2 x = 5 or -5 but if you really want to use formula x^2 + 0 x - 25 = 0 x = [ -0 +/- sqrt (0 + 100) ] / 2 x = +/- 10/2 x = +/- 5
April 15, 2014

math (matrix)
I assume you meant the determinant 24 x + 3 x^2 + 6 x + 10 - 9x = 25 3 x^2 + 21 x -15 = 0 x^2 + 7 x - 5 = 0 x =-7/2 +/- (1/2) sqrt(69) What a mess, assume you have a typo. To invert matrix use http://matrix.reshish.com/inverse.php
April 15, 2014

math
100 * (1/8)/ (8/12+3/12) = 100 * (1/8) / (11/12) = 100 * (3/24)(22/24) = 100 (3/22) = 13.6%
April 13, 2014

Calc III
not a valid transformation, zeros on diagonal check with http://www.wolframalpha.com/widgets/view.jsp?id=d6a52679e750c30e320a7094ec975598
April 13, 2014

math
pi D = 3.14159 * 13
April 13, 2014

math
1" = 50 miles IS 2" = 100 miles so if 2" is only 25 miles, we will need four times as long a sheet of paper. so 4
April 13, 2014

whoops, arithmetic error
t^2 - 2 t - 3 = -(1/5)(h) t^2 - 2 t = -h/5 + 3 t^2 - 2 t + 1 = -h/5 + 4 (t-1)^2 = -(1/5) (h - 20) so max height at one second of 20 meters
April 13, 2014

Math 10
that is a parabola (quadratic) 5 t^2 - 10 t - 15 = -h find the vertex by completing the square t^2 - 2 t - 7.5 = -(1/5)(h) t^2 - 2 t = -h/5 + 7.5 t^2 - 2 t + 1 = -h/5 + 8.5 (t-1)^2 = -(1/5) (h - 42.5) so max height at one second of 42.5 meters
April 13, 2014

math
r = 24 in /gift * 1 yd / 36 in * number of gifts r = (24/36) * number of gifts cost = 2 * r
April 13, 2014

math
10 apples/basket 2 baskets/bushel so 20 apples per bushel min 900/20 = 90/2 = 45
April 13, 2014

math
number of cuts = (n-1) amount wasted = 1/16 * (n-1) amount total = (3/32) n + (1/16) n - 1/16 so 25 16/32 = 5 n/32 -2/32 816/32 +2/32 = 5 n/32 818 = 5 n n = 163.6 so 163
April 13, 2014

free-body diagram help
You only need the horizontal forces in this case because the friction force(not the coefficient) is given. 45 - 13 = 20 a work done = change in kinetic energy = (45 - 13) (4) Newton meters or Joules
April 13, 2014

Physics
weight of ladder = m g = W force down on floor = W max friction force = .3 W so horizontal force on top of ladder from wall = . W Take moments about base of ladder .3 W (L sin T) = W(L/2)cos T .3 sin T = (1/2) cos T tan T = .5/.3 T = 59 degrees Notice that the ladder length ...
April 13, 2014

maths
1.875 km * 2 * 6 = 22.5 km
April 12, 2014

Maths
3 a = 4 2 a = -3 there is only one variable here, a there is no intersection of lines so no solution by elimination or substitution: a = 4/3 for the first equation a = -3/2 for the second equation
April 12, 2014

Math
Very interesting but as far as I know these are your apparel dimensions. I do not read minds and have no idea what you are looking at. Is it a triangle maybe?
April 9, 2014

math PLEASE HELP!!!!!
girth = 2(32+49) = 162 times length 41 = 6642 ft^2 base area = 32*41 = 1312 times height = 64288 ft^3 Why on earth do you need a formula? Draw a picture.
April 9, 2014

Circle Geometry
draw a picture line from center of circle to tack hits circumference at a right angle (because it is a radius) and therefore that is the closest point to the tack. also line from circle center to ground is 90 deg so right triangle d is hypotenuse center to tack r^2 + 58^2 = d^...
April 9, 2014

Calculus Help Please!!!
Q = Qi e^-k t when Q/Qi = 1/2 .5 = e^-k t ln .5 = - 4 k so k = (ln .5) / -4 Q = 800 e^ (ln .5)t / 4 k = .1733 so Q = 800 e^-.1733 t if t = 30 Q = 800 e^-5.2 Q = 4.4 mg 1/800 = e^-.1733 t ln(1/800) = -.1733 t 38.6 days enough already
April 9, 2014

Physics multiple choice questions
Ah, first you try and it is too late because I have to go to sailing practice. Maybe Steve will help.
April 8, 2014

Calculus Help Please
ln x y = lnx + ln y ln x + ln y -cos^-1(x-1) = x 1/x + (1/y) dy/dx+(1/[1-(x-1)^2])^.5 = 1 1/x +(1/y)dy/dx+(1/(-x^2+2x)^.5) = 1 (1/y) dy/dx = 1 - 1/x - [1/(x(2-x))^.5 dy/dx = y { 1 - 1/x - [1/(x(2-x))^.5 } when x = 1 ln x + ln y -cos^-1(x-1) = x 0 + ln y - pi/2 = 1 ln y = 1 + ...
April 8, 2014

Physics
east is + 1500 * 25 - 2000 * 0 = 3500 v
April 8, 2014

Physics
change in momentum of car A = 1250 (40) = 50,000 toward the west so change in momentum of car B is 50,000 toward the east 50,000 = 2000 (east velocity - -25) 25 = east velocity + 25 east velocity = 0 stopped it dead in the water :)
April 8, 2014

physics
change in temp = 90 - 15 = 75 deg C heat in = mass * specific heat * change in temp = 12 kg * specific heat * 75 deg C I do not know specific heat in Joules or calories or kilocalories or whatever you are using in your class / kilogram deg C
April 8, 2014

college alg.
Different initial up speed but use : http://www.jiskha.com/display.cgi?id=1396965991#1396965991.1396967805
April 8, 2014

college algebra
h = hi + Vi t - (1/2) g t^2 in ancient English units this is h = Hi + Vi t - (1/2) 32 t^2 If Hi = 0 Vi = 128 ft/s then h = 128 t - 16 t^2 for h = 144 144 = 128 t - 16 t^2 16 t^2 - 128 t + 144 = 0 t^2 - 8 t + 9 = 0 t = [ 8 +/- sqrt(64 -36) ]/2 t = 4 +/- sqrt 7 t = 1.35 t = 6.65
April 8, 2014

Calculus Help
y = sin [ pi*(t^2+5)^-.5 ] y' = pi [cos pi*(t^2+5)^-.5] * [-.5(2t)](t^2+5)^-1.5 if t = 2 y' = pi {cos pi/ 3} *[-2] [ 1/27 ] = -(2pi/27) cos (pi/3) but cos pi/3 = 1/2 so -pi/27 CHECK MY ARITHMETIC !!!! =
April 7, 2014

Calculus Help Please!!!
sin 2 x ---- 2 x + .... as x -->0 tan x also ---> x so 2x /(2x - x) 2x/x = 2
April 7, 2014

Math
least common multiple 8 = 2*2*2 30 = 5*2*3 so we need a 5, 3 twos, and a 3 so 120
April 7, 2014

math word problem PLEASE HELP
r = ribbon = 15 (5 3/8) - 10(3/4) r = 15 (43/8) - 60/8 r = (15*43 - 60 )/8 = 585/8 = 73 1/8 yards
April 7, 2014

Physics
Or approximate in your head 1 atm = 10^5 Pascals approx so 2.38 atm = about 2.3 *10^5 pascals which is 2.3 * 10^2 kilopascals or 230
April 7, 2014

Physics
use Google type 2.38 atm = Pascal get 2.38 atm = 241 153.5 pascals which is 241 Kilopascals
April 7, 2014

Physic II
300 g = .3 kg so .3 * .11 * 5 thousand calories
April 7, 2014

chemistry
.75 * .5 = .375 mols of Na2CO3 2 HCl + Na2CO3 --> 2 NaCl + H2O +CO2 so we need .375 * 2 = .75 mols of HCl .75 * 1.25 = .9375 Liters
April 7, 2014

math
505200000000000 = 505,200,000,000,000 = 505.2 * 10^12 = 5.052 * 10^14 so YES :)
April 7, 2014

Fine number but what about it?
What is the question
April 7, 2014

Chemistry
Yes, but Mols of H2SO4 in ONE LITER 3 M means 3 mols in a liter 9 M means 9 mols in a Liter
April 7, 2014

Math
sin 2 x = sin x when x = 0, 180, 360 etc
April 7, 2014

science/math
1. No If it hits at 42 from the SURFACE that is 90-42 = 48 from the normal. The reflected ray will also be 48 from the normal. 2. NO 27 + 27 = 54
April 7, 2014

Physic II
sh in cal/kg deg C = .19 *1000 = 190 heat in = mass * sh * delta T 450,000 = 100 * 190 * (50-T) 23.68 = 50-T T = 26.3 deg C
April 7, 2014

physics
1) 90 - 42 2) 27 * 2
April 7, 2014

I already answered this
Please post once. Both are very wrong.
April 7, 2014

Math
You percent is percent that will FAIL It asks for the ones that do not fail.
April 7, 2014

Math
100 - 30.2
April 7, 2014

Math
Atta go :) You are welcome.
April 7, 2014

Math
dQ/dt = 200(-.0488) e^-.0488 t
April 7, 2014

Math
A = Ai e^-kt .5 = e^-14.2 k ln .5 = -14.2 k k = .0488 so Q = 200 e^-.0488 t
April 7, 2014

Math
Now I did problems very similar to this for you earlier. You try and I will check if I am around.
April 7, 2014

Math
You sure are having quite a time with these exponential functions! y = 190 [ 1- .955 e^-(.25 t) ] If t = 9 y = 190 [ 1 - .955(.105) ] = 190 [ 1 - .1 ] = 171 cm In other words it has reached 90% of max length in 9 years now dy/dt = 190(-.955) (-.25)(.105) = 4.76 cm/year c) when...
April 7, 2014

Physics
a) Vx = 65 cos 30, Vy = 65 sin 30 b) Vx =125 cos 40, Vy = -125 sin 40 c) Vx = 5.3 sin 30 , Vy = 5.3 cos 30 of course sin 30 = 1/2 and cos 30 = sqrt3/2
April 7, 2014

Calculus
Tyler, if yu do not know how to use parentheses try to type it with lines like 1 -------- (3 t - 1) or something.
April 7, 2014

Physics
I am not going to look at this until I see some attempt by you to balance forces and moments.
April 7, 2014

physics
Pick some time over which the dB/dt takes place, say t = one second. Then dB/dt = 3.2/1 = 3.2 T/s then you can get i for that dB/dt then i * t = i * one second
April 7, 2014

World history
Netherlands ? :)
April 7, 2014

Math
2.7^3 = 19.683 15 * 19.683 = 295.245
April 6, 2014

statistics
by the way that calculator uses x - mean for z instead of (x-mean)/sigma
April 6, 2014

statistics
Here is an online normal distribution calculator: http://davidmlane.com/hyperstat/z_table.html
April 6, 2014

statistics
well, you have enough data points to use normal distribution rather than computing with binomials forever and a day. Otherwise use a program or spreadsheet to compute all the binomial coefs and powers and products mean = n p = 200 * .6 = 120 sigma^2 = 120 (.4) = 48 so sigma = ...
April 6, 2014

Math
we have already done a half life one but anyway ds/dt = k s ds/s = k dt ln s = k t + c when t = 0, ln si = c si is initial size ln s = k t + ln si ln (s/si) = k t s/si = e^kt 2 = e^k(30 min) ln 2 = 30 k k = .0231 1,000,000/50 = e^.0231 t ln (20,000) = .0231 t t = 428.6 = 429 ...
April 6, 2014

Math
.5 = e^-k T ln .5 = - k T T = -.693/-k = .693/k b) T = .693 / .0001074 = 6454 years
April 6, 2014

physics
1 C 2 less, maybe you run over the mark from the first one on the track just as the rear can explodes, and the two marks on the track are together :)
April 6, 2014

Physics
On earth I assume weight on first line = (86.4+20.8)(9.81) weight on second (lower) line = 20.8 (9.81)
April 6, 2014

physics
in the horizontal direction the ball has no acceleration once let go (no horizontal force) so now it is 9 m/s^2 down by the way, g on Mars about the same as earth ? FALSE
April 6, 2014

physic
40 g = .04 kg .04 [25 (sh ice) + heat of fusion + 100 (sh water) + heat of vaporization + 5 (sh water vapor at 1 atm) ]
April 6, 2014

algebra 2
An = A1 + (n-1)d average = (A1 + An)/2 sum = average * number of terms = n (A1 +An)/2 = (n/2) [ 2 A1 + (n-1)d ] here = (11/2) [ -24 + (10)5 ] = (11/2) (26) = 11 * 13 = 143
April 6, 2014

physics
z = 5 * 10^5 ohms i = 1/(5*`10^6) = .2 *10^-6 = 2 *10^-7
April 6, 2014

physics
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/rlcser.html
April 6, 2014

English
B. ok C. Based on his very frail appearance, a mugger might SURMISE that he would be SUSCEPTIBLE to a strong arm attack; however, that would be a great mistake.
April 5, 2014

English
My version A. I said that he was HYPOCRITICAL because he pretends to be filled with PIETY, but I know that he is a bigger sinner than I am. I wouldn't even mind that if on Sundays in church he wasn't so POMPOUS.
April 5, 2014

social studies check answers
1. disagree 2. no idea 4. agree
April 5, 2014

English
loud and intense manner.
April 5, 2014

algebra
.25 A = 48 A = 48/.25 = 48 * 4 = 192 (2/3) 192 = 2 (64) = 128
April 5, 2014

Read what you typed
Lots of dimensions missing.
April 5, 2014

Math
ds = sqrt (dx^2 + dy^2) dx = -5sin t +5 sin5t dx^2= 25sin^2 t -50sint sin5t+25sin^2 5t dy = 5 cos t -5 cos 5t dy^2= 25cos^2 t-50costcos5t +25 cos^2 5t luckily sin^2 + cos^2 = 1 dx^2+dy^2=50-50(sin t sin 5t+costcos 5t) but sin a sin b + cos a cos b = cos(a-b) = 50 - 50 cos 4 t...
April 5, 2014

Physics
delta L/L = (T/area) / E = (215*9.81 /2*10^-5) / 8*10^10 = ( 1054 * 10^5 ) / 8*10^10 = 132 * 10-5 so delta L = (3.5)(132*10^-5) = 461 * 10^-5 = .00461 meters = .461 cm
April 5, 2014

Physics
Tension in cable = T Force up at end from cable = T sin 37 compression Force toward wall = T cos 37 max friction force = .485 T cos 37 up vertical forces on rod sum to 0 2 Fg = .485 T cos 37 + T sin 37 2 Fg = .989 T T = 2.02 Fg take moments about intersection of rod and wall ...
April 5, 2014

Physics 141
Hey. I just did that.
April 5, 2014

Physics 141
Distance axle above step edge = .33 - .125 = .205 Angle T is angle between straight down from Axle and the top edge of the step so cos T = .205/.33 T = 10.58 deg sin T = .184 Take moments about the top edge of the step. F * .205 clockwise (my step is on the right) m g * .33 ...
April 5, 2014

Physics 141
T = 1/4 so f = 4
April 5, 2014

Physics 141
after one period T, (8 pi T) = 2 pi so T = 1/4 so f = 1/T = 4
April 5, 2014

math
first .2*9.45 = 1.89 remaining length = 9.45 - 1.89 = 7.56 so piece 2 + (piece 2 - .12) = 7.56 2 * piece 2 = 7.68 piece 2 = 3.84
April 5, 2014

Civil War
It did sort of.
April 5, 2014

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