Friday

January 20, 2017
Total # Posts: 28,803

**Social Studies**

I tend to agree with you. He was no fan of slavery but wanted to stick within the law which defined the slaves as property at the time.

*November 28, 2016*

**ah, Betta :)**

2.5*4 = 8+2 = 10

*November 28, 2016*

**math**

rate is 40 person hours/ room (40 p hr/ r)/(4p) = 10 hr/room

*November 28, 2016*

**trig**

whew, good !

*November 28, 2016*

**trig**

you could say that r = -6 and theta = pi/2 but that is no good, r must be +

*November 28, 2016*

**trig**

x = 0 y = -6 that is 6 units directly below the origin so r = 6 = sqrt(0^2+6^2) you are three quarters of the way around to two pi

*November 28, 2016*

**trig**

Hey, sketch this stuff on a rough graph.

*November 28, 2016*

**trig**

r = 6 straight down = (3/4)(2 pi) = 3 pi/2 = 1.5 pi

*November 28, 2016*

**science**

No, I am not going to Google Young's modulus of steel for you, E L = 0.6 m r = 0.0025 m A = pi (.0025)^2 delta L/L = 2.5(9.81)/(E A) delta L = 0.6*2.5*9.81/(E*pi*.0025^2)

*November 28, 2016*

**maths**

(48 p/200g)500g = (5/2)*48 = 5*24 = 120p

*November 28, 2016*

**algebra**

x + x+15 = 43 2 x = 28 x = 14 x+15 = 29

*November 28, 2016*

**Physics**

assume constant torque = constant angular acceleration alpha omega = alpha * t theta = omega initial*t +(1/2)alpha t^2 129 * 2pi/360 = 2.25 radians so 2.25 = 0 + .5 alpha (36) alpha = .125 rad/s^2 omega = alpha t = .125*6 = .75 rad/s

*November 28, 2016*

**trig**

You are welcome.

*November 28, 2016*

**4 pi/3**

4 pi/3 = pi + pi/3 in quadrant three see your original question

*November 28, 2016*

**Asfand - your pi/3 problem**

is 4 pi/3 in third quadrant

*November 28, 2016*

**maths**

54/.75

*November 28, 2016*

**maths**

Huh? 6*5.8

*November 28, 2016*

**Physics**

v = omega r dv = omega dr omega = 2 pi radians/(24*3600)seconds dr = 18.2 dv = 2 pi (18.2) /(24*3600)

*November 28, 2016*

**maths**

No problem :) You are welcome.

*November 28, 2016*

**maths**

r^2 = 25 +25*3 = 100 so r = 10 tan theta = sqrt3 in quadrant III 60 degrees below x axis pi + pi/3 = 4 pi/3 you are in third quadrant because x and y are negative

*November 28, 2016*

**Math**

out = in / 10

*November 28, 2016*

**History**

no NO NO ! no Hey, google all four topics!

*November 28, 2016*

**Check Answers SOCIAL STUDIES PLEASE**

yes yes but perhaps more commonly D yes

*November 28, 2016*

**Math**

what if y = x^3 ----> y =x^1/3 is function y = x ---> y = x is function 2 y = x^3 + x ---> y+y^3 = 2x y(1+y^2) =2 x for x = 0 y = 0 or y = +/-i more than one value off y for x = 0, no, no for function

*November 28, 2016*

**SCIENCE**

I suppose 4, but I would call it habitat re-creation to combat habitat fragmentation.

*November 28, 2016*

**Social Studies**

C is certainly true historically but I do not know what period you are talking about. (Russo-Japanese war, World War 2 ??)

*November 28, 2016*

**What excerpt ?**

I do not see your excerpt. I would be inclined to agree with all of the above but have not seen what you read.

*November 28, 2016*

**SCIENCE**

LOL, that was easy ;)

*November 28, 2016*

**Social Studies**

Gee, Google it. I would go back to the original thin Spanish settlement claim to Texas, New Mexico, Arizona, California and parts of other states and the fact that they did not send a lot of settlers thereby letting people from the US settle. Be sure to cover the fact that ...

*November 28, 2016*

**Algebra 2**

They mean a,b,c,d by the way + and complex pair -5 +/- 2 i sqrt 5

*November 28, 2016*

**Algebra 2**

http://www.wolframalpha.com/widgets/view.jsp?id=3f4366aeb9c157cf9a30c90693eafc55

*November 28, 2016*

**Math**

6.8 min / 1 mile 30 min * 1 mile/6.8 min = 4.41 miles

*November 28, 2016*

**math**

1. yes 2. yes, works for any old y 3. just like 2 4. yes

*November 28, 2016*

**PHYS-041-Keiler: Physical Science**

assuming 5730 year half life a = Ai e^-kt a/Ai = .5 = e^-k(5730) ln .5 = -k(5730) k = 1.21 *10^-4 so a = 22 e^-(1.21*10^-4*11400) = 22 * e^-1.38 = 22* .252 = 5.54 kg

*November 27, 2016*

**physics**

T = 2 pi sqrt(L/g)= (2 pi/sqrt g)L^.5 = 1 second at 22 deg so you can get initial L dT/dL = (2 pi/sqrt g).5 /sqrt L dT/dt = dT/dL * dL/dt so what is dL/dt dL/L = 24*10^-6 dT dL /dT = 24*10^-6 L dL/dt = dL/dT *dT/dt = 24*10^-6 (-.625) L so dT/dt = [(2 pi/sqrt g).5 /sqrt L][24*...

*November 27, 2016*

**Physics**

assume I = (1/2) m r^2 for disk = (1/2)(6.5)(r)^2 Torque = I alpha where alpha = ang acceleration = a/r T = tension in rope so torque = T * r = I (a/r) T = I a/r^2 = (.5 m )a=.5(6.5)a now the block force down = m g force up = T ma = mg - T T = mg-ma = 2.5(g-a) so putting them ...

*November 27, 2016*

**Stoichiometry**

4.5 grams, look below at earlier question

*November 27, 2016*

**Math**

12 marbles to start drew one yellow 4/12 then 11 marbles of which 3 are yellow 3/11 so 4/12 * 3/11 = 1/11

*November 27, 2016*

**maths**

cost = 1040 - 240 = 800 (240/800)100 = 30% profit 12 * 6.50

*November 27, 2016*

**Stoichiometry**

(75/1000).6 = .045 mol CaCO3 = 100 g/mol so 4.5 grams

*November 27, 2016*

**Stoichiometry**

CaCl2 + Na2CO3 ---> CaCO3 +2NaCl one to one in mols of each 75 *.6 = x * .4

*November 27, 2016*

**maths**

2400 * .15 2400 * 1.15 .8*2400 before VAT

*November 27, 2016*

**maths**

0.8 Liters * n = 36 Liters n = 38/0.8 = 45 cans ======================= b makes no sense to me. It is a typo I think.

*November 27, 2016*

**Math**

t/5 = (t-5)10 t = (t-5)50 t = 50 t -250 49 t =250 t = 250/49

*November 27, 2016*

**Probablility**

I assume you never use the same machine twice first cardio = 4/10 = 2/5 second = 3/9 =1/3 third = 2/8 = 1/4 fourth = 1/7 product = 2/5 *1/3*1/4*1/7 = 1/210 now weight first =6/10 = 3/5 second = 5/9 third = 4/8 = 1/2 fourth = 3/7 product = 3/5 * 5/9 * 1/2 * 3/7 =1/14 so 1/210...

*November 27, 2016*

**Algebra**

7-5.375 = 1.625 for left and right margins 1.625 - .3125 = 1.3125 for right margin do the vertical problem the same way

*November 27, 2016*

**Algebra**

75*20 + 95*30 = x * 50

*November 27, 2016*

**Math**

5 * 3/1 = 15

*November 26, 2016*

**pre calculus**

100(-.5 -.866i) - 50 - 50 sqrt3 i

*November 26, 2016*

**pre calculus**

we want r(cos T + i sin T) r = sqrt ((-2)^2 +2^2) =sqrt 8 =2 sqrt2 -2 = r cos T = 2 sqrt 2 cos T cos T =-sqrt 2 / 2 T = 3 pi/4 2 = R sin T = 2 sqrt 2 sin T sin T = sqrt2 /2 T = 3 pi/4 all right so z =2 sqrt 2[cos .75 pi+isin .75 pi]

*November 26, 2016*

**AP Calculus**

well lets think it might be like a hot stone cooling down to some room temperature Tf Google Newton's law of cooling T = Ts +(To-Ts)e^-(k t) To is your original 1900 time Ts is your final time in 2100 or whatever which is the fastest one can ever go k is a constant that ...

*November 26, 2016*

**physics**

Your second method is the right way to go.

*November 26, 2016*

**pre calculus**

I think you probably mean: e^(a+bi) =e^a e^bi = e^a (cosb+isinb) then e^i? = e^(0+i?) =(e^0)(cos pi+isinpi) = 1(-1 + 0) or e^i? = -1

*November 26, 2016*

**7th grade Pre- Algebra**

R/5 - 6 = -1 add 6 to both sides R/5 +0 = 6 - 1 R/5 = 5 now multiply both sides by 5 (R/5)5 = (5)(5) R = 25

*November 26, 2016*

**missing question**

[f(x)-f(a)] /(x-a) = 7 as x-->a is the definition of the derivative f'(a) = 7

*November 26, 2016*

**math**

df/dx = 4 x^2/[x^3 +3] at x = -1 df/dx = 4/[2] = 2 so f(-1+dx) = f(-1) + 2 dx here dx = -.1 so f(-1-.1) = -3 +2(-.1) = -3 -.2 =-3.2

*November 26, 2016*

**Physics**

t is in seconds 40 t = 42(t-120)

*November 26, 2016*

**math**

sin ? = 0 slope = cos ? = -1 f(x) = sin(?) -1(x-?) = -(x-?)

*November 26, 2016*

**science**

global positioning systemhttp://www.safewise.com/blog/10-wearable-safety-gps-devices-kids/ ( of course I use GPS to get around the bleak ocean but that is old stuff:) sampling whale snot with drone http://shop.whale.org/pages/snotbot tidal power generation systems http://...

*November 26, 2016*

**Electronics**

http://www.electronics-tutorials.ws/rc/rc_1.html

*November 25, 2016*

**Math**

s^3 = 512 s = 512^(1/3) calculate s = 8 A = 6 (s^2) = 6 * 64

*November 25, 2016*

**Calculus application of sin function**

v = dh/dt = sin pi t then h = - (1/pi)cos pi t but h = A cos (2 pi t/T) so A = -1/pi pi = 2 pi /T so T = 2 so in the ean h =-(1/pi) cos pit = -(1/pi)cos(2 pi t/2) B) h =-(1/pi) cos pit v = dh/dt = sin pi t a = dv/dt = pi cos pi t C)1/pi D) cos 0 = 1 so at t = 0 , 1 , 2 etc E) ...

*November 25, 2016*

**second graph link not rights**

http://www.wolframalpha.com/widget/widgetPopup.jsp?p=v&id=8d8e2c27bcaa121d6ee0de4b98774bb4&title=Polar%20Graphs&theme=blue&i0=r%3D2(2-sin^2%C9%B5)^%C2%BD%20&i1=0&i2=Pi%2F2&podSelect=&showAssumptions=1&showWarnings=1

*November 25, 2016*

**calculus**

I suspect you mean: r=2(2-sin2?)^½ that makes me nervous that since you do not type exponents you might mean 2-sin^2 ? instead of what your typed. I will assume that first graph it here with sin 2? http://www.wolframalpha.com/widget/widgetPopup.jsp?p=v&id=...

*November 25, 2016*

**Science**

mass = 150/g or about 15 kg but who needs it? x = A sin w t v = Aw cos wt a = -Aw^2 sin wt = -w^2 x ============================= when x = .2 = A sin w t v = 5 = Aw cos w t a = +20=+Aw^2 sin w t = +w^2x =============================== so w^2 x = w^2(.2) = 20 w^2 = 200/2 = 100 ...

*November 24, 2016*

**Maths**

x^2 y = V G = 4x+y = 6 ================== y = 6-4x x^2 (6-4x) = V now do the complete the square thing like I did in your other problem to find the vertex of the parabola

*November 24, 2016*

**Engineering**

4 x = 800 x = 200 feet on a side square ========================= prove that square is max area A = x y P = 2 x + 2 y perimeter so x + y = P/2 A = x (P/2 - x) = -x^2 +P/2 x x^2 - (P/2) x = A find vertex,complete square x^2 - (P/2)x + P^2/16 = -A + P^2/16 (x-P/4)^2 = -(A-P^2/16...

*November 24, 2016*

**math**

s = standards d = deluxe 12 s +18 d = 360 ____divide by 6 s + d = 25 ________multiply by 2 2 s + 3 d = 60 2 s + 2 d = 50 -------------- d = 10 then s = 15

*November 24, 2016*

**Physics**

assume you mean 5 m/s^2 50 *1000/3600 = 13.9 m/s v = 13.9 - 5 t 0 = 13.9 - 5 t t = 13.9/5 average speed during stop = 13.9/2 d = (13.9/2) (13.9/5) or d = Vi t - .5 (5) t^2 d =13.9(13.9/5)-.5 (5) (13.9^2)/5^2 = .5 *13.9^2/5 the same

*November 24, 2016*

**physics**

ub^2 = .25 ua^2 average speed for initial slowing = .5(ua+ub) assume constant a t = .05/.5(ua+ub) = .1/(ua+ub) v = Vi +at ub = ua + a t ub-ua = a (.1)/(ua+ub) .1 a = -(ua^2-ub^2) .1 a = - (.75 ua^2) a = -7.5ua^2 now complete trip 0 = ua + a t t = ua/7.5ua^2 = 1/(7.5ua) d = Vi...

*November 24, 2016*

**Math**

There are lots of different ways. perhaps the easiest to understand uses the distributive property 12 = 10 + 2 13 = 10 + 3 (10 + 2) (10 + 3) = 10 (10+3) + 2 (10+3) = 100 + 30 + 20 + 6 = 100 + 50 + 6 = 156 ========================== You can shorten that by saying 10(13) + 2(13...

*November 24, 2016*

**Physics**

If there is no moment (torque) then there is no change of angular momentum [ I omega = constant] If they are not opposite in direction through the same point, they cause a moment, called a "couple"

*November 24, 2016*

**algebra**

n and 2 n 2 n - n = 20 n = 20 and so answer = 2n = 40

*November 23, 2016*

**Gaussian Elimination Method**

LOL, forgot the old easy stuff :)

*November 23, 2016*

**Gaussian Elimination Method**

to check, put it back in -4(-1) -(-2) = ? yes 6 12(-1) -2(-2) = ? yes -8

*November 23, 2016*

**physics**

m v^2/r horizontal m g down tan theta = mg/(mv^2/R)where theta is angle down from horizontal but cos theta = .7/2.8 so theta = 75.5 deg so tan theta = 3.87 so 3.87 = mg/mv^2/R = 9.81/(v^2/.7) v = 1.33 m/s m v^2/R = .4*1.77/.7 = 1.01 m g = .4*9.81 = 3.92 T^2 = 1.01^2 +3.92^2 T...

*November 23, 2016*

**Math**

9*10^-3 LY (5.88*10^12 mi/LY) = 52.92 * 10^9 mi = 5.292 * 10^10 mi

*November 23, 2016*

**math!**

q = first questions/min 2 q = final que/min t min for first ten 48 - t min for final 11 q t = 10 so t = 10/q q t + 2q(48-t) = 21 10 + 96q - 20 = 21 96 q = 31 q = 31/96 questions/min so twice that = 62/96 to finish ======================== check t = 960/31 = 30.97 min 48-t = 17...

*November 23, 2016*

**Algebra 2**

.75 x + .42 y = .5784 (100) x+y = 100 ============================ .75 x + .42 y = 57.84 .75 x + .75 y = 75 ---------------------- -.33 y = - 17.16 y = 52 x = 48 E

*November 23, 2016*

**Physics**

h f = 14.7 eV lambda = c T = c/f c about 3*10^8 m/s

*November 23, 2016*

**Physiscs**

well the length is L sqrt 13 but who cares? force up from floor = m g = 3g (because wall is smooth none up there) force sideways from wall = F thus force sideways at floor = F toward wall Now moments about center clockwise mg * 2L/2 = m g L counter clockwise F*1.5 L + F*1.5 L...

*November 23, 2016*

**physics**

80 km/hr * 1 hr/3600s * 1000 m/km = 22.2 m/s tan T = v^2/r / g = v^2/gr tan T = 22.2^2/(981) tan T = .502 T = 26 deg 39 min

*November 23, 2016*

**Physics**

rho g h 1000 * 9.81 * 20 = 196,200 Pascals = 1.94 atm gage (over 1 atm) or 2.94 atm absolute

*November 23, 2016*

**Physics**

done already

*November 23, 2016*

**Calculus**

Oh, but I said where x = +/- infinity

*November 23, 2016*

**Calculus**

Oh, yes :)O

*November 23, 2016*

**Calculus**

Oh my, look around x = 0 and x = 1 and x = infinity and x = -infinity http://www.wolframalpha.com/input/?i=plot+1%2F(x(x-1))

*November 23, 2016*

**Math**

a) sin is + in I and II b) cos is - in II so there only c) hard to sketch here from origin up 7 distance 25 x^2 + 7^2 =625 and x is - x^2 = 625 - 49 = 576 x = -24 so point is at (-24,7) cos C = -24/25 tan C = -7/24

*November 23, 2016*

**Math**

cos /sin = -1 = cotan 90 + 45 360 - 45

*November 23, 2016*

**Consider the linear programming problem**

You are welcome.

*November 23, 2016*

**Consider the linear programming problem**

which we could have seen without doing the problem :) The potato seed costs less and the profit is more

*November 23, 2016*

**Consider the linear programming problem**

maximize 150 x + 50 y x + y <=70 20 x + 60 y <= 3000 x>= 0 y>= 0 x+y >=1 to fill in input form only http://www.wolframalpha.com/widget/widgetPopup.jsp?p=v&id=1e692c6f72587b2cbd3e7be018fd8960&title=Linear%20Programming%20Calculator&theme=blue result 10500 at (70,0)

*November 23, 2016*

**Calculus**

f' = 10 - 10/x^2 f" = 0 - 10 [ -2/x^3] = 20/x^3 I do not see anyplace where the curvature passes through zero except at x = +/- infinity

*November 23, 2016*

**Linear Programming to Maximize Profit**

You are welcome.

*November 23, 2016*

**Linear Programming to Maximize Profit**

Oh my heavens I have done so many linear programming problems tonight! s uses 6 plastic d uses 3 plastic so 6 s + 3 d </= 300 s uses 4 metal d uses 8 metal so 4 s + 8 d </= 608 s </=22 maximize 10 s + 2 d I get 332 at (22,56) using http://www.wolframalpha.com/widget/...

*November 23, 2016*

**math**

7x = 1.40 x = .20 2x = 0.40 4x = 0.80 5x = 1.00 7x = 1.40 sum = $3.60

*November 23, 2016*

**simplex method**

For instructions using Simplex with pivots etc see http://en.wikipedia.org/wiki/Simplex_algorithm

*November 23, 2016*

**doing with linear programming**

http://www.wolframalpha.com/widget/widgetPopup.jsp?p=v&id=1e692c6f72587b2cbd3e7be018fd8960&title=Linear%20Programming%20Calculator&theme=blue max = 3220 at (12,50)

*November 23, 2016*

**Calculus**

This is a closed path check first if field is potential in which case integral is zero F = z^2 i + 2xy j + 3y^2k del cross F = 0 ???? nope no way so first line = 3 i + 0 j + 0 k F dot line = Fx *3 = 0*3 = 0 second line in x from 3 to 3 = 0 in y from 0 to 3 = 3 in z from 0 to 1...

*November 23, 2016*

**Calc**

or rather curl F

*November 23, 2016*