# Posts by Damon

Total # Posts: 29,753

**math**

No one knows, you only talk about tons, not how many rods in a ton. We can do tons (1/8)(3/4) = 3/32 ton

**Algebra**

(810,000 - 520,000)/(2013 - 2000)

**Calculus**

what is f(8)? -6x^2 + 96x + 7 =-6(64) +96(8) + 7 = -6(64) +12(64) + 7 = 6(64) + 7 = 391 now you say f(10) is bigger? -6(100) +96(10) + 7 -600+960+7 367, nope , disagree

**Calculus**

this is a parabola since we have a negative coef of x^2 it opens down (sheds water) the real question is, where is the vertex? complete the square 6 x^2 -96 x = 7 x^2 - 16 x = 7/16 x^2 -16 x + 64 = 64 7/16 (x-8)^2 vertex at x = 8 Yes, you are right , e.

**Math**

You are welcome.

**Math**

204/4 = 51 408/8 = 51 510/10 = 51 miles per hour 51mi/1hr so A.

**Math**

D =f(t)

**ARCHIMEDES PRINCIPLE**

http://mathworld.wolfram.com/CircularSegment.html

**geography**

well, in Gloucester MA we are about 70 west of Greenwich England so go a bit further west, like Chicago is about 87 W, St Louis MO is 90 ! then look north or south of there Look at a map or globe or maritime/air chart

**Science**

LOL, it was about the horizontal plane, but yes that could happen

**How to upset me**

That did it !

**Science**

NEWTON'S FIRST LAW !!!!!!!!!!! There is NO external force on this system therefore There is NO CHANGE of momentum. Never ever forget that !!! D. !!!!!!

**Physics!!!!!!**

force * time = change in momentum 360 * t = .18*26 solve for t a = change in velocity/time = -26/t Vi = 26 d = Vi t + (1/2)a t^2 d = 26 t - (1/2)(26)t d = 13 t

**The Simplex Method**

therefore at the intersection of 5x+10y?560 and 50x+20y?1600

**The Simplex Method**

http://www.wolframalpha.com/widget/widgetPopup.jsp?p=v&id=1e692c6f72587b2cbd3e7be018fd8960&title=Linear%20Programming%20Calculator&theme=blue ========================== 3220 at (12,50) ========================== maximize | function | 60 x + 50 y\ndomain | x + y<=80 && 5 x...

**calculus**

3 of length x 1 of length y A = x y length of fencing = 3x+y = 600 so y = (600 - 3x) A = x(600 - 3x) = -3 x^2 + 600 x dA/dx = -6 x + 600 min or max A when 6 x = 600 or x = 100 then y = 300 A = x y = 30,000 ft^2 or about 3/4 of an acre

**Describing Data**

you mean the mean frequency I suppose? add them up and divide by 4

**Algebra 2**

use first choice, area from values mean 450 sd 50 between 400 and 500 output is .6827 or 68% are between well that is a little less thsan .7*160 = 112 so 109

**Algebra 2**

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

**physics**

I assume in series E = i R + L di/dt let i = a (1- e^-kt) then di/dt = a*k e^-kt when t =oo , E=i R i = E/R = a so a = E/R so i = (E/R)(1-e^-kt) di/dt = (E/R) k e^-kt when t-->0, i = 0 and di/dt = a k so E = L di/dt = L a k = L(E/R)k so k = R/L so In the end all that we ...

**science**

9.81(33.1+69.0)

**Probability Help**

This is a famous problem https://en.wikipedia.org/wiki/Birthday_problem

**Math**

PsyDAG gave you the answer. There are 16 blocks.

**homework dump**

So where is your attempt to do these?

**Calc**

the slope, -1 = f' is the same

**Maths**

d^2 = (4*3)^2 + (4*4)^2 = 4^2 (9+16) = 4^2*5^2 so d = 4*5 = 20

**Algebra 1**

y = k x 25 = k (-140) k = -5/28 y = k (36) = -(5/28)(36) = - 5*9/7 = -6.43

**Math**

sqrt a /sqrt b = sqrt (a/b) like sqrt 16/sqrt 9 = sqrt(16/9) = 4/3 sqrt(12 r^7r^-5 s^7s^-2) sqrt (12 r^2 s^5) 2 r s^2 sqrt (3s)

**Math**

sqrt [128/81 *m^3/m^1 *n^5/n^7 ] = sqrt [2*64/81 * m^2 /n^2] = (8/9)(m/n)sqrt 2

**LIT**

x + y = 37 y -2x = 4 -----------subtract second equn from first 3 x = 33 x =11 then y = 26

**Geometry**

The angles are both in corner A so they add up to 90 degrees 4x+8 = 5x-8 x = 16

**where is M?**

if m is at the center then diagonal = 2(5x+1) which is the same as the other diagonal 42 5x+1 = 21 5x = 20 x = 4

**same question**

as below

**College Math**

about .5 https://en.wikipedia.org/wiki/Birthday_problem 1 - [(1/365)^41 (364*363*362....324)]

**Calculus**

side = x height = y volume = x^2y = 4000 so y = 4000/x^2 area = A = x^2 + 4 x y A = x^2 + 4 x (4000/x^2) A = x^2 + 16000/x min or max when dA/dx = 0 0 = 2x -16000/x^2 16000 = 2 x^3 x^3 = 16000 x = 25.2 y = 4000/x^2 = 6.3

**Science**

radiation primarily from sun

**math**

-8 is to the left of +10 on your number line is it not? Therefore -8 < +10

**Calculus**

cos x dx = e^y dy dy/dx = cos x /e^y but e^y = sin x so dy/dx = cos x / sin x = cot x

**Algebra**

how about we multiply the entire equation 1/p+1/(p-45) = 1/30 by 30p(p-45) 30(p-45) +30p = p(p-45) 30 p - 1350 + 30 p = p^2 -45 p p^2 -(45+30+30)p + 1350 = 0 p^2 - 105 p + 1350 = 0

**Algebra**

y^2 = 16 x

**not doing them all**

This is just a reverse of your last problem with different numbers

**now wait a minute**

I have showed you how to do these. speed = sqrt (T/u) u = mass/length distance for wave to travel in one period = 2L (because half a wave is fundamental) T = distance/speed frequency = 1/T

**physics last one**

speed of sound there? Call it v (maybe around 350 m/s) goes twice L 2 L = v T = 2.2 v L = 1.1 v

**Algebra**

p(x) is a parabola opening down(sheds water) therefore the vertex is at the top p So use complete square to find vertex (if you do not know any calculus) -10 x^2 + 100 x = p + 210 x^2 - 10 x = - (1/10)(p+210) x^2 - 10 x + 25= -(1/10)(p+210)+25 (x-5)^2 = -(1/10)(p+210-250) x = ...

**physics**

string length = 0.97 meter m = 0.0036 kg u = mass/length = .00371 half a wavelength = 0.61 meter speed = sqrt (570/.0031) = 429 m/s time to go half a wavelength = .61/429 = .00142 seconds time for a wavelength = .00284 s f = 1/time = 351 Hz

**physics**

mass/unit length = .73/31 = .0235kg/m speed = sqrt (T/u) where T = tension in Newtons which is kg m/s^2 and u is mass per unit length in kg/m so speed = sqrt (1100/.0235) = 216 m/s time = distance/speed = 31/216 = .143 s looks like piano wire :)

**Math**

8 quarts [1 drink/ (1/4 quarts)] = 8 * 4/1 = 32 drinks

**Huh?**

You are asking some old retired professor who has no idea what your test is about? Perhaps you better post one of the thirty questions and tell us what about it you are having trouble with or do you just want me to do it for you? Why would I do that?

**MATH**

3 a = 5 so a = 5/3 4a - 5 = 20/3 - 5 = 20/3 - 15/3 = 5/3

**math**

145 + 2.4*145 -58 = 435 145/435 = .3333

**math**

(Agree with Coolmath )

**math**

clara raised x ali raised 1.2 x shan raised 1.2 x - 58 x = 5/4 (1.2 x - 58) 4 x = 6 x - 290 2 x = 290 x = 145 now you do the rest

**PLEASE HELP SOCIAL STUDIES CONNECTIONS ACDEMY 6th**

yes

**PLEASE HELP SOCIAL STUDIES CONNECTIONS ACDEMY 6th**

arrrgggghhhh Read Reed!

**math check my answers please**

agree agree

**Math**

You are welcome.

**Math**

then my guess is my answer, about 2500, B

**typo?**

no way it is 1010 feet wide assuming you mean about 10 feet and d is 80.8 (or is it 808 ?) surely not a mile and a half pi d = about 3*81 = about250 pi d* 10 = about 2500

**math**

x yellow 12 - x green first draw x/12 second draw (x-1)/11 so both (x^2-x)/132 = 5/33 33(x^2-x) = 660 x^2 - x - 20 = 0 (x-5)(x+4) = 0 x = 5 because it is hard to visualize a negative yellow marble

**math**

brown, 9 x black, 4 x white, 8 x = 16 so x = 2 18 + 8 + 16

**Calculus applications**

Now you want the max moment and where the moment will be max where its derivative, the shear, is zero S = w (L/2 - x) = 0 so the moment is max where x = L/2, the middle of course How much is it? M = w (L^2/4 -L^2/8) = wL^2/8 which is wl (L/8) which is the weight * L/8

**Calculuhttp://www.jiskha.com/display.cgi?id=1480944543s applications**

Calculus applications - Damon, Monday, December 5, 2016 at 9:24am If you want to draw it it is a seesaw with no one on it w pounds per foot of weight down (+) and a force up of wL = total weight at center :) Note that moment must be zero at both ends and will be maximum at the...

**Calculus applications**

first go here http://www.jiskha.com/display.cgi?id=1480944543

**Math**

749 is bigger than 500 so 123,166---> 123,167 123,167,000

**Algebra**

3x+2y=34 x+y = 15 so y = 15-x 3x +2(15-x) = 34 3x + 30 -2x = 34 x = 4 y = 11

**which do you guess?**

NOT B

**Algebra 2**

I bet you mean x^2 + y^2 = 16 well we could do it right or we could cheat and say we want a circle with center at (-8 ,-3) (x+3)^2 + (y+3)^2 = 4^2

**URGENT 4TH GRADE MATH**

You are welcome.

**URGENT 4TH GRADE MATH**

733.2

**URGENT 4TH GRADE MATH**

you want 22 characters? 733.166666666666666666

**URGENT 4TH GRADE MATH**

well, I know 6*7 = 42 so 6*700 = 4200 but 6*800 is too big so use 700 and then we have 4399-4200 = 199 left over 6* 30 = 180 so use 30 and I now have 730 and 19 left over 6*3 = 118 so use 3 and I now have 733 and one left over so 733 1/6 733 with a remainder of one

**NO**

You do not have 49 teachers!

**VERY, VERY URGENT 4TH GRADE MATH!!!!!!!!!!!!!!!!!!**

so 6 groups of 7 would require 42 teachers but 7 groups of 7 needs 49

**VERY, VERY URGENT 4TH GRADE MATH!!!!!!!!!!!!!!!!!!**

Hurry please, I am waiting on pins and needles. I know that 7*6 is around 42 and 7*7 is about 49

**MATH URGENT!!!!!**

slope 1 = (3-3)/(4-0) = 0 slope 2 = 2 2-0 = 2

**wait a minute**

it PRODUCES 150 J of heat? Usually one must put heat into an engine to get work out (boil water, burn gas). This is either a typo or a magic trick.

**Physics**

100(work out/heat in) the heat out to the other system is lost to this problem. Note that it is 110 which is what is left over after you take 40 out of your 150 see http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heaeng.html

**whoops**

cos x =cos 2x cos 2x = cos^2x -sin^2 x where does cos^2x -(1-cos^2x) =cos x cos x = 2 cos^2x-1 2 cos^2x -cos x - 1 = 0 (2 cos x +1)(cos x -1) = 0 cos x = 1 or cos x = -1/2 x = 0 or 2 pi n or x = 2 pi/3 +2 pi n

**Calc**

why do you think the domain is from -pi to 3pi ? I think it is all real x df/dx = 2 cos x -2 cos 2x (hoping you did not mean sin^2x) at 7 pi 2sin 7pi = 0 in fact sin any number of pis is zero so we are looking for where the slope is 0 that is where cos x = cos2x well, that is ...

**what do you mean?**

What you typed y = a(x - h)2 + k, a ? 0 a line with slope 2a and y intercept 2 a h + k is VERY different from y = a(x - h)^2 + k, a ? 0 a parabola with vertex at (h,k) and upright (holds water)

**precalculus**

x 7-4 = 3 and directrix is above vertex (sheds water) so a = -3 (x+2)^2 =-4*3 (y-4)^2 = -12(y-4)^2 =

**you do this one**

Hey, I did the other one

**wait a minute**

I did the other one, you can find the x component of your speed around the circle.

**Calculus 1**

f(x,y) = x^3y^2 df = (df/dx) dx + (df/dy) dy df/dt=(df/dx) dx/dt + (df/dy) dy/dt but f is a constant = 2916 df/dx = 3x^2y^2 = 3*81*4= 972 df/dy = 2x^3y = 2*729*2= 2916 so 0 = 972 (dx/dt) + 2916 (2) dx/dt = -6

**Math**

y = cos (x)+ 3 x interchange x = cos y + 3 y if y = 0, x = 1 + 0 x' = -sin y + 3 but y = 0 at x = 1 dx/dy = 3 dy/dx = 1/3

**Math**

remember 1 worked for y, so not it works for x :)

**Math**

dy/dx = 5 x^4 + 6 x^2 + 1 but x is 1 here we know already dy/dx = 5+6 + 1 = 12 interchange dy/dx = 1/12

**try interchanging x and y**

y = x^5 + 2 x^3 + x - 1 exchange x and y x = y^5 + 2 y^2 + y - 1 now use 3 for x 4 = y^5 + 2 y^2 + y 1 works for y

**Vectors**

|a| = sqrt(3^2+4^2) about 5 I think. Now you do the other. Remember when you square a negative you get a positive.

**Calculus applications**

You are welcome.

**correction**

the shear, not the moment, changes instantly at the center

**Calculus applications**

If you want to draw it it is a seesaw with no one on it w pounds per foot of weight down (+) and a force up of wL = total weight at center :) Note that moment must be zero at both ends and will be maximum at the middle changing signs instantaneously M = w L (x/2) - w x^2/2 S...

**science**

ahh, which comes out to zero if he is not accelerating up or down :)

**science**

1500 * 9.8 Newtons down and if he is sitting quietly 1500* 9.8 N up from the ice on his frozen fur.

**Like ALWAYS**

Momentum after = Momentum before. Even when you get to relativity !

**Science Physics**

There is one thing you can really count on, Newton's First Law. If there is no external force on a system, the momentum remains CONSTANT Momentum before = Momentum after. If I could underline that PERIOD I would do so. You can not count on mechanical energy being the same ...

**Math**

w + L = 108 L = w + 30 so w + w + 30 = 108

**physics**

F = m a F = 3kg* 5m/s^2 = 15 Newtons a = F/m a = 15N/12.2kg a = 1.23 m/s^2

**statistics**

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

**math double check please**

yes, two 2s and a 3 yes, 420 * 3