# Posts by Damon

Total # Posts: 29,623

**I do not believe you**

I think you have a very fundamental typo. We are talking about a constant rate of inflation here I bet you mean f(x) = 0.69 (1.03)^x in other words TO THE POWER x that would be 0.69 when x = 0 years, now 0.69 * 1.03 after one year 0.69 * 1.03 *1.03 after two years 0.69 *1.03*1...

*December 17, 2016*

**Algebra 1- Help please**

option 1 is not linear because it does not change by the same amount every year. It does not have a constant slope. option 2 increases by 100 per year, constant slope, straight line, linear ----------------------- a = A y^n 1100 =A y 1210 = Ay^2 1331 = A y^3 --------------- ...

*December 17, 2016*

**SS, PLZ HELP ME FAST!!!!**

hint: Japanese eat a lot more fish than people on the great plains eat.

*December 17, 2016*

**Calculus!! HELP!!**

1) The sides of the triangle shown increase in such a way that (dz/dt=1) and (dx/dt=(3dy/dx)) At the instant when x = 12 and y = 5, what is the value of dx/dt? ========================= You do not say but I suspect this is a 5,12,13 right triangle. If I am guessing right about...

*December 17, 2016*

**Maths**

I do not know what using rotational axis means but this is an ellipse 4(x^2-2x) +9(y^2+6y) = -4 complete squares 4(x^2-2x+1)-4+9(y^2+6y+9)-81=-4 4(x-1)^2 +9(x+3)^2 = 81 (x-1)^2/4.5^2 + (x+3)^2/3^2 = 1 ellipse

*December 17, 2016*

**Math**

area = (1/2)12*5 = 30 hypotenuse BC = 13 the area = 30 = (1/2)13*AD AD =60/13

*December 17, 2016*

**Math**

120,000/50 = 240,000/100 = 2400

*December 17, 2016*

**Probability and distribution**

16 total to start I could draw a white, then blue 6/16 * 7/15 or I could draw a blue, then white 7/16 * 6/15 add them 2(42/240) = .35

*December 17, 2016*

**math**

Try then (a^9/2)^3 = a^27/ 8

*December 16, 2016*

**History homework question**

Oh, 20th Century Leaders :) Civil Disobedience.

*December 16, 2016*

**History homework question**

Hudson River school is paintings. I do not understand the second question.

*December 16, 2016*

**American history**

well, if only about in Americas (not India, Africa etc) Spain - get gold out, make Catholics France - get fur and fish out, make Catholics. Do not send many French people, just a few missionaries and trappers. England - make trading partners that grow food and ship masts and ...

*December 16, 2016*

**physics**

v = omega r 10 = omega(2) omega = 5 radians/second Ac = v^2/r = omega^2 r = 25*2 = 50 m/s^2 F = m a = .5 *50 = 25 N (not 25.5)

*December 16, 2016*

**is (-2x)^-3 3 root of -2x?**

(-2x)^-3 = 1/(-2x)^2 = 1/[-2x(-2x)(-2x)] = 1/[(-8)(x^3)] =-1/(8 x^3)

*December 16, 2016*

**Maths**

subtract area of inside circle from area of outside circle radius inside = 28/2 = 14 radius outside = 14+3.5 = 17.5 so pi(17.5^2-14^2)

*December 16, 2016*

**Huh**

Your minister of education has two brains and they are headed for somewhere else?

*December 16, 2016*

**Jong**

Hair?

*December 16, 2016*

**typo**

x = 1 and y = 1 at t = 0 y = .5 x + b 1 = .5 + b b = .5 y = .5 x + .5

*December 16, 2016*

**calc**

y = sin t + cos^2 t - sin^2 t dy/dt = cos t -2cost sint -2 sint cost at t = 0 dy/dt = 1 x = cos t +2 sin t cos t dx/dt = -sint -2sin^2t+2 cos^2t at t = 0 dx/dt = 2 dy/dt / dx/dt = 1/2 = slope x = 1 and y = 1 at t = 0 y = 1 x + b b = 0 y = x

*December 16, 2016*

**Math**

1/(x+h) - 1/x (x - x - h)/(x^2+xh) -h/(x^2+xh) divide by h -1/(x^2+xh) let h--->0 -1/x^2 sure enough

*December 16, 2016*

**linear programming problem**

the intersection with p max is of 5x+10y=560 and 50x+20y=1600 x = 12, y=50 and p = 3220 http://www.wolframalpha.com/widget/widgetPopup.jsp?p=v&id=1e692c6f72587b2cbd3e7be018fd8960&title=Linear%20Programming%20Calculator&theme=blue

*December 16, 2016*

**calculus!**

at x+h y = 1/(3-x-h) at x y = 1/(3-x) subtract 1/(3-x-h) -1/(3-x) [(3-x) -(3-x-h)]/[(3-x-h)(3-x)] [ h]/[ x^2-6x+xh-3h+9] divide by h 1/[x^2-6x+9 +xh-3h] let h --->0 1/(x-3)^2

*December 16, 2016*

**Math - Coordinate Geometry**

3y = 2 x + 3 is y = (2/3)x + 1 slope = 2/3 so y = (2/3)x + b if parallel -4 = (2/3)6 + b b = -8 so y = (2/3)x-8 3 y = 2 x - 24

*December 16, 2016*

**math**

3078+582 = 3660 =3*1000 + 0*100 + 7*10 +8*1 +0*1000 + 5*100 + 8*10 +2*1 =3*1000 + 5*100 +15*10 +10*1 =3*1000 + 6*100 + 5*10 +10*1 =3*1000 + 6*100 + 6*10 + 0*1 = 3660

*December 16, 2016*

**Science**

Now I am sure you know these answers (although I consider a fossil biological). I would be willing to review them but not just answer them.

*December 16, 2016*

**Geometry**

I guess it is supposed to be a triangle? If so ac can not be longer than 11+13 = 24 and it can not be shorter than 13-11 = 2 DRAW IT !

*December 16, 2016*

**Sociology**

They mean the same thing to me. Homogeneous is opposite to diverse.

*December 16, 2016*

**calculus**

LOL, either way I do physics, I find t easier to visualize step by step.

*December 16, 2016*

**calculus**

dV/dt = 3ft^3/min(1 min/60s) = .05 ft^3/s so V = .05 * 30 = 1.5 ft^3 at 30 s V = (4/3) pi r^3 so r = 0.71 ft at 30 s dV/dr = 4 pi r^2 (the surface area of course) but dV/dt = dV/dr * dr/dt so dr/dt = dV/dt / (4 pi r^2) dr/dt = .05 /(4 pi*.71^2) = .00789 feet/second

*December 16, 2016*

**Gauss-Jordan elimination**

-3 +3 -21 +3 +2 -4 ============= http://www.idomaths.com/gauss_jordan.php ===================== 1 0 2 0 1 -5 x= 2, y = -5

*December 15, 2016*

**HELP SCIENCE**

Which do you think? What does north and south pole mean?

*December 15, 2016*

**augmented matrix**

No unique solution, equations are the same +3 +1 -11 -9 -3 +33 http://www.idomaths.com/gauss_jordan.php 1 0 -3.667 0 0 0 x = -3.6666.... or -11/3 y can be anything equation 2 is -3 times equation 1 Therefore the two lines are the same, they do not intersect, there is no solution

*December 15, 2016*

**Physics**

3.) An 80.kg climber with a 20.0 kg pack climbs 8848 m to the t?op of mount everest. how much work did the climber exert in the climbing the mountain ==================== 100 kg up 8848 meters 100 * 9.81 * 8848 = 8,679,888 Joules (That is the useful work, his efficiency would ...

*December 15, 2016*

**Physics**

When the string is cut, the bob has only horizontal velocity u. It keeps that horizontal velocity u until it hits the ground because there is no horizontal force after that. So there are two separate problems here: 1. How far does it go at constant speed u for time t? 2. If ...

*December 15, 2016*

**Math 4th Grade**

You are welcome, good luck.

*December 15, 2016*

**Math 4th Grade**

280 = 2 x m 28 = 2 x 14 280 = 2 x 140 so m = 140 I am not sure why I would want to do it that way though. If you can handle 2 x 14 I bet you could handle the tens part.

*December 15, 2016*

**Sets**

Union is 107 Intersection is 13 draw Venn diagram 69 + A alone = 107 so A alone = 38 plus A and B = 38+13 = 51

*December 15, 2016*

**Measurement/math**

35*circumference = 100

*December 15, 2016*

**Algebra**

check it yourself like this: 11 + (-.7) = -15(y) ????? I think x = 19 and y = -2 http://www.idomaths.com/gauss_jordan.php with +1 15 -11 +2 -5 +48

*December 15, 2016*

**Math**

1/4 + what = 11/12 ???? 3/12 + what = 11/12 well how about 8/12 so 1/4 + 8/12 = 11/12 or 1/4 + 2/3 = 11/12

*December 15, 2016*

**Algebra II**

What is an L ?? Perhaps a Newton??? if cm^2/then D for Dyne anyway v = k/p 16 cm^3 = k / 20L/cm^2 k = 16*20 v = 16*20/2.2 = 145 cm^3

*December 15, 2016*

**maths calculas part**

144/4 = 36 36*36 = 1296 m^2 now how did I know it was square? 2x+2y = p = perimeter so x+y = p/2 so y = p/2-x A = x y = x(p/2-x) A = (p/2)x - x^2 or x^2 - (p/2)x = - A x^2 -(p/2)x + (p/4)^2 = -A + p^2/16 [ x - (p/4)]^2 = - (A-p^2/16) so vertex at area = (p/4)^2 and x = y = p/4...

*December 15, 2016*

**Maths**

if there are five of them and the median is five I think five is an integer a b c d e c = 5 (a+b+c+d +e)/5 = 5 so a+b+5+d+e = 25 a+b+d+e=20 with d and e >5 and a and b <5 well what if a = 1 b= 2 d= 7 e = 10 1 2 5 7 10

*December 14, 2016*

**precalculus**

P(k+1) = p(k) + 5

*December 14, 2016*

**Math**

volume is proportional to length cubed for similar geometry 2 times length is 4 times area 2 times length is 8 times volume so 1875(16/40)^3 = 1875(.064) = 120cm^3

*December 14, 2016*

**physics**

centripetal acceleration: To stay at the same radius, a water particle of mass m must have a force on it inward of m v^2/r. Until it hits the walls of the container, that force is missing. If the water particle happens to hit upon a hole in the wall or dribbles down the wall, ...

*December 14, 2016*

**Science 6**

B skunk eats toads I do not think toads and mice compete for who has the honor of being eaten by the fox

*December 14, 2016*

**Algebra**

1 q + 1 n = 13 1 q + .2n = 8.2 ---------------subtract .8 n = 4.8 so 6 nickels

*December 14, 2016*

**precalculus**

as you can see in the other answers, yes 4y^2+8y-2

*December 14, 2016*

**precalculus**

I guess you might mean: x = t^2-6 y = .5t - 1 ????? if so, just substitute 2y = t -2 t = 2 y +2 then x = 4(y^2+2y+1) -6 x = 4y^2 + 8y - 2 sketch that parabola

*December 14, 2016*

**precalculus**

hyperbola opening right and left center at (0,0) crosses x axis at -1 and +1 slopes at corners = +/- 2

*December 13, 2016*

**linear programming**

maximize p p = 6s+5b s+b</=70 b>/=20 s>/=10 sketch a graph there are two intersections to check (s,b) = (10,60) here p= 60+300 = 360 and (s,b) = (50 ,20) here p=300 + 100 = 400 (winner)

*December 13, 2016*

**physics**

Fup = 400 Fdown = 9.81*50 =491 so accelerating down a down = 91/50 m/s^2

*December 13, 2016*

**Science-y Math-y Stuff**

0.8 x = 4,000

*December 13, 2016*

**Science**

There was this guy in Sicily , Archimedes: http://www.math.nyu.edu/~crorres/Archimedes/Lever/LeverIntro.html http://en.wikipedia.org/wiki/Lever

*December 13, 2016*

**Physics**

alternatively you can use conservation of energy kinetic energy at bottom = potenial energy at top (1/2)mVi^2 = m g h so Vi^2 = (2 g h) h = Vi^2/2g

*December 13, 2016*

**Physics**

get vetical component of velocity up at ground, call it Vi. If shot at angle A up from horizontal then Vi = V sin A during flight acceleration = -g or 9.8 m/s^2 down or 32 ft/s^2 down speed up = v = Vi - g t = Vi -9.8 t or = Vi -32 t at top, v = 0 so t = Vi/9.8 or t = Vi/32 ...

*December 13, 2016*

**Physics**

average speed during initial slowdown = (80+40)/2 = 60km/h 60 km/h * t = 0.5 km t = 5/600 hours = (1/120)hr (1 hr/120)(60min/hr)(60s/min) = 30 seconds so a = change in speed/time = -40 km/hr /30 s = (-40 * 1000 m/3600s)/30s = -(4/3)/3.6 m/s^2 so Vi = (40/3.6) m/s final v = 0 =...

*December 13, 2016*

**I THINK I FIGURED IT OUT!**

8 works if you reverse order

*December 13, 2016*

**Math**

2/5 = 10/x x = 25

*December 12, 2016*

**Pre-Calculus**

well if you mean (x^2-1) it is D but if you really mean (lim x^2) -1 which is what you typed it is A

*December 12, 2016*

**Algebra**

9(r-2)<-73 or 9(-r+2)<-73 first one: 9 r -18 < -73 9 r < -55 r < -55/9 sure looks like a solution second one: -9 r + 18 <-73 9 r -18 > 73 9 r > 91 r >91/9 so second solution

*December 12, 2016*

**pre-calculus**

square :) side = 50/4 = 25/2 A = x y P = 2x+2y = 50 so y = (25-x) A = x(25-x) = 25 x - x^2 x^2 -25 x = -A x^2 - 25 x + (25/2)^2 = -A + 625/4 x = 25/2 sure enough so y = 25/2 and A = 625/4 = (25/2)^2

*December 12, 2016*

**Algebra**

1. 8 is a factor of 12?? 12/8 = 3/2 = 1.5 2 55/5 = 11 3. You said what P was 4 and 5 are incomplete problem statements both A and B are subsets of U 2 is the intersection of A and B

*December 12, 2016*

**physics**

suspect 1000 kg not 100 kg but anyway gravity down = 9.81 *100 = 981 N acceleration down = v^2/r Up force = F so 981 - F = ma = 100 v^2/r so F = 981 - 100 (400)/200 = 781 N but as you know if it is a real car I think 7810 N

*December 12, 2016*

**Physics**

I will guess that you mean the current leaves the battery and runs through r2 then splits and runs through r1 and r3 in parallel then joins again and runs through r4 back to the battery. If I guess right then r1 and r =3 in parallel are r1 r3 /(r1+r3) = 90*40/(130) = 3600/130...

*December 12, 2016*

**SS HEEELLLPP!!!**

I think that is a matter of opinion, not history. Check your text for what they say. I am not sure the Great Wall was such a success militarily. There seem to have been plenty of intruders from the north after. My own opinion is that the most important thing was the ability of...

*December 12, 2016*

**Physics**

x momentum = 16*30 = 480 g cm/s -x momentum = 4*50 = -200 g cm/s total x momentum = +280 g cm/s That will NOT CHANGE ! new mass = 16 + 4 = 20 g so 20 * Vx = 280 Vx = 14 cm/s

*December 12, 2016*

**8TH GRADE MATH**

60 sqrt 2 hypotenuse = sqrt (60^2+60^2) = sqrt (2 * 60^2) = 60 sqrt 2 = 84.85

*December 12, 2016*

**physics**

Vi = 30 sin 30 = 15 = initial speed UP u = 30 cos 30 = 26 = horizontal speed until caught v = Vi - 9.81 t at top v = 0 (First answer) so at top t = 15/9.81 = 1.53 seconds upward bound THE ACCELERATION IS -9.81 m/s^2 the ENTIRE TIME that it is airborne

*December 12, 2016*

**check for typo**

The way you wrote it k x^2 = (3k-5) x = +/- sqrt(3 - 5/k) but I wonder if you mean kx^2 -3kx+5 which would be x = [3k +/- sqrt(9k^2-20k) ]/2k

*December 12, 2016*

**Chemistry**

k m/r^2 so (3/4)(804)

*December 12, 2016*

**algebra**

I guess maybe you mean 6/ (?3 + 2 ) if so then [ 6/(?3+2)] * [(?3-2)/(?3-2)] 6(?3-2)/[3-4] -6?3 + 12 which is B

*December 12, 2016*

**Physics**

Archimedes said Force up = weight of fluid displaced. It displaced 6.4-5.6 = 0.8 kg of water so its volume is V = .8 kg (m^3/1000kg) = 8*10^-4 m^3 so its density is (6.4 /8)10^4 kg/m^3 =8000 kg/m^3 might be iron

*December 11, 2016*

**physics**

suspect STATIC is 0.68 .68 m g = starting Force .55 m g = constant velocity Force

*December 10, 2016*

**Algebra**

1-4k >= -11 and -1+4k >=-11 -4k >= -12 _and ___4k>=-10 4 k <= 12 __and_____k>=-2.5 k <= 3 note arrow reverse when signs changed so in the end between -3and +3 -2.5 <= k <= 3

*December 10, 2016*

**Physics**

You could have done that, patience :)

*December 10, 2016*

**Physics**

Total force up =100(9.81) = T1 sin37 + T2 sin 53 Total horizontal force = 0 = T1 cos 37 - T2 cos 53 use that to get T1 and T2 now for example moments about left end T2 sin 53 *5 = 100*9.81* X

*December 10, 2016*

**Math**

3(-2)(-2) -2(-2)(3) + 10 12 + 12 + 10 34

*December 9, 2016*

**system of equations**

Oh, and you might want to click on "very detailed solution" :)

*December 9, 2016*

**system of equations**

Click on Gauss Jordan there of course.

*December 9, 2016*

**system of equations**

5 -3 -34 10 -5 -65 (-5, +3) see http://matrix.reshish.com/gaussSolution.php

*December 9, 2016*

**whoops sorry**

xp = 100 +/- 50sqrt2 so about 30 (NOT 70 AS I SAID) if xp = 30 yp = .01x^2 = 9

*December 9, 2016*

**Calculus**

y = a x^2 100 = a(10,000) a = .01 so our parabola is y = .01 x^2 now a tangent to that parabola must pass through (100,50) slope = .02 xp at parabola y = (.02xp)x + b 50 = 2 xp + b b = 50-2xp but yp = .01 xp^2 and yp =.02xp^2 +50-2xp .01 xp^2 = .02xp^2 + 50 - 2 xp .01 xp^2 -...

*December 9, 2016*

**where is the equation?**

I might be able to solve for x given that y is 15 if I had any idea what the equation was.

*December 9, 2016*

**la**

Well I suppose your own :)

*December 9, 2016*

**math help**

3 < 4 three is less than four 4 > 3 four is greater than three and by the way 4<=4 four is either less than or equal to four

*December 9, 2016*

**physics**

31 cos 35

*December 9, 2016*

**work and energy PHYSICS**

at O where h = 0, all kinetic, E= (1/2)m Vi^2 + 0 at Q, not moving any more E =0 + m g Q Total energy during whole trip E = (1/2)m v^2 + m g h as h goes up to Q, v goes down to 0 using the start and finish points (1/2) m V^2 = m g Q Vi^2 = 2 g Q Vi = sqrt(2gQ)

*December 9, 2016*

**Physics - studying for finals**

for the second part, out in a phase angle .05 sin[(2pi/.75)(x+.375t) -PHI] (2pi/.75)(0.50) -PHI = 0 PHI = 2 pi (.5/.75)

*December 8, 2016*

**Physics - studying for finals**

A =0.0500 m L = 0.750 m T = 1/5 = 0.2 goes .75 m in .2 s so v=.75/2 = .375m/s for constant phase (x+vt) the+vt makes it left to make it go 2pi for every wavelength l or time T sin [2 pi (x+vt)/L] now the size .05 sin[(2pi/L)(x+vt)] more numbers in .05 sin[(2pi/.75)(x+.375t)]

*December 8, 2016*

**Math**

(x-1)(3x-2)(x-4i) but (x-4i)is not allowed alone, we also need its complex conjugate (x-1)(3x-2)(x-4i)(x+4i) I get 3x^4-5x^3+50x^2-80x+32

*December 8, 2016*

**Math**

8x + x = 9 x = 63 x = 7 so 8x = 7*8 which is about 56 as I remember.

*December 8, 2016*

**physics**

v = g t = 9.81 * 10 = 98.1 if no air drag but with friction terminal speed is 21 so 21 m/s

*December 8, 2016*

**Math**

x = -2 is a vertical line through the point (-2,0). Y can be anything.

*December 8, 2016*

**Math (optimization) really confused**

three fences of length x two fences of length y A = xy = 225 so x = 225/y p = total length = 2y + 3 x we want to minimize p p = 2 y +3(225/y) dp/dy = 0 at max or min dp/dy = 0 = 2 -675/y^2 2 y^2 = 675 y^2 = 337 y = 18.4 x = 225/18.4 so what is 2y+3x?

*December 8, 2016*

**History Please Help**

They were people, humans.

*December 8, 2016*

**Physics**

F * 0.24m = 31Nm so F = 31 Nm/0.24m

*December 8, 2016*

**Physics**

try throwing something up and see if time stops and moved backwards while the object falls back down.

*December 8, 2016*

**what do you think ?**

The force on this object is F = - m g so a = -g What are your answers?

*December 8, 2016*