Monday

October 20, 2014

October 20, 2014

Total # Posts: 18,972

**Math**

3/10 are boys 7/10 are girls total boys = x total girls = x+200 total students = 2x+200 (3/10)(2x+200) = x 6 x + 600 = 10 x 4 x = 600 x = 150
*September 6, 2014*

**math 1 question**

yes 2.5 times r = 2.5 r
*September 6, 2014*

**Math**

1.45 c = 79.95 c = 79.95/1.45
*September 5, 2014*

**ALGEBRA**

five and six is eleven (x+5)(x+6) seven - two (x-7)(x+2) I bet you mean 9x^2-16 which is difference of two squares a^2-b^2 = (a+b)(a-b) (3x+4)(3x-4)
*September 5, 2014*

**Physics**

v = Vi - 9.81 t 20 = Vi - 9.81 (2.1) solve for Vi then Use that Vi to get v at t = 4.7
*September 5, 2014*

**physics**

east components 2880 cos 42 = 2140 south components 2880 sin 42 + 4360 = 6287 magnitude = sqrt (2140^2+6287^2) tan (angle) = 6287/2140
*September 5, 2014*

**Physics**

I mean west is - x direction :)
*September 5, 2014*

**Physics**

West is - y direction Ax = -20.0km*sin(35.0º) NOTE NEGATIVE Ay = 1.650km or 20.0km*cos(35.0º)? Bx = 18.0km*cos(75.0º) By = 1.420km or 18.0km*sin(75.0º)? Rx = Ax + Bx Ry = Ay + By and Rz = 1.650 - 1.420 R = sqrt (Rx^2 + Ry^2 + Rz^2)
*September 5, 2014*

**INTEGRAL CALCULUS PLEASE HELP!!!**

I assume you mean the integrals or areas are 4 , 9 and 1 Sketch it all I can say is that the integral from 4 to 17 (not 9 to 17) is -12 because 4 + integral 4 to 17 + 9 = 1 I do not even know what 2) means. If it is integral F(x) dx - 4 intregral dx then answer above - (4(17...
*September 5, 2014*

**Physics**

On earth that 40 N weight would correspond to about m = W/g = 40/10 = 4 kilograms of mass which is around 8 pounds. This collie is actually a toy poodle. 200 kg ? That is about 450 pounds weight on earth which means the average patient stepped on the scale with her husband and...
*September 5, 2014*

**Algebra**

Just did, see below.
*September 5, 2014*

**Physics**

well, sure, but there is much more to it. As you stated the problem: x = (1/2) a t^2 so a = 2 x/t^2 or t = sqrt (2 x/a) but that is a gross oversimplification of what is going on with constant acceleration a if a = some constant acceleration v = Vi + a t where Vi is initial ...
*September 5, 2014*

**math**

hard to say
*September 5, 2014*

**algebra**

line of form y = m x + b m = (Y2/Y1)(X2-X1) = (4-0)/(2-1) = 4 check with other points (like (12-0)/(4-1) ) y = 4 x + b put a point in to find b 0 = 4(1) + b b = -4 so y = 4 x - 4
*September 5, 2014*

**algebra**

y = x (.658 - .000407 x) where is y = 0 ? at x = 0 and at x = .658/.000407 = 1617 ft long (that is part B) this is a parabola that crosses the x axis at 0 and 1617 so the vertex, max height, is halfway between at x = 808 what is the height? y = -.000407 (808^2) + .658(808) = ...
*September 5, 2014*

**math 101**

7.9 * sqrt 2
*September 5, 2014*

**English**

Does the second sentence not seem a bit strange? Does it need the word "ever" ?
*September 5, 2014*

**math**

5 3/12 - 3 10/12 is 4 15/12 - 3 10/12 is 1 5/12
*September 5, 2014*

**Math PLease help**

put in the form y = m x + b then m is the slope 3 y = -6 x + 12 2 y = -2 x + 4 y = -2 x + 4 y = -1 x + 2 -2 is not - 1 so not parallel -2 is not -1/-1 so not perpendicular
*September 5, 2014*

**Math PLease help**

6 x - 14 = 30 x + 54 + 28 assuming that = is a + 24 x = -96 x = -4
*September 5, 2014*

**Physics**

The first phase is easy if you have constant acceleration because the average speed until the stop is Vi/2 = 5 m/s t to stop = 148.3 / 5 = 29.7 seconds a = change in velocity/change in time = -10/29.7 = -.337 m/s^2 phase 2 displacement = 37.7 - 148.3 = -110.6 meters -110.6 = (...
*September 4, 2014*

**Physics**

because when the one that was fired upward gets down to cliff level it is traveling downward at the same initial speed down as the first one was.
*September 4, 2014*

**Math**

tan 72.5 = h/5
*September 3, 2014*

**physics**

Newton #2 - Force = rate of change of momentum so force * time = change in momentum (impulse) 100 * 5 = 25 * v
*September 3, 2014*

**Homework**

c = Q / [ w(T1-T2) ]
*September 3, 2014*

**Algebra**

6 * 2.8/4
*September 2, 2014*

**math**

9+21 = 30 456 is about 500 87 is about 100 about 30 thousand six hundred 30,600
*September 2, 2014*

**social studies**

Well, he failed to establish a permanent presence in North America and he and the other Vikings who followed him made enemies of the natives so that a permanent establishment probably would have required an army (or smallpox or measles to eliminate the locals). I am not sure ...
*September 2, 2014*

**algebra**

depends if your text includes zero as a natural number negative numbers are not natural numbers either 0 through 10 which is 11 or one through 10, which is ten
*September 2, 2014*

**math**

2 x + 4 y = 14 3 x - 4 y = 6 --------------- add 5 x = 20 x = 4 now go back and get y
*September 2, 2014*

**math**

These lines are the same. There are an infinite numbers of solutions, a y for every x you pick.
*September 2, 2014*

**Math**

70,016,090 32,000,232,000
*September 2, 2014*

**Shurley English**

That is an analogy. I did not say it was good analogy :)
*September 2, 2014*

**Shurley English**

a way something is like something else. Your arteries and veins are analogous to the water supply and wastewater piping system in your city :)
*September 2, 2014*

**Algebra 2 Answer Check**

You do not need me to operate the calculator Victoria :)
*September 2, 2014*

**ratios**

There are probably more cars than trucks, like 3/1
*September 2, 2014*

**math**

^%$*&@ math teachers think they are navigators. The "heading" is 215, NOT the "bearing". You take a bearing on something outside the ship, for example it might be the direction of a lighthouse. south is 180 so 35 degrees west of south answer = 145 cos 35
*September 2, 2014*

**Algebra 2**

sqrt 8100 = 90 ft baselines so 90 sqrt 2
*September 2, 2014*

**Algebra 2**

90/6 = 15 ft^2 each so the side of each square is sqrt 15 2 sqrt 15 + 3 sqrt 15 + 2 sqrt 15 + 3 sqrt 15 :)
*September 2, 2014*

**Algebra 2 Answer Check**

11 yes
*September 2, 2014*

**Algebra 2 Answer Check**

1. 2/√3 A: 2√3 / 3 yes 2. -18/√6 A: -3√6 yes Add or subtract. 3. 4√3 - 9√3 A: -5√3 yes 4. √8 - 15√2 A: -13√2 yes 5. √45 + √20 A: 5√5 yes 6. 2√48 + 2√12 = 2 sqrt (4*12) + 2 sqrt 12 = 4 ...
*September 2, 2014*

**Algebra 2. HELP**

You are welcome.
*September 2, 2014*

**Algebra 2. HELP**

I think you can graph straight line t = 0 to t = 8 (end of shift, you still have 18 left for the next shift :( n = 42 to n =18 -3(5) + 42 = 27
*September 2, 2014*

**What is P?**

1.05^3 = 1.157625 1.157625 * x = 8600 x = 7429.00
*September 2, 2014*

**algebra**

5 r </= 1 r </= 1/5 so what is the problem?
*September 2, 2014*

**Math 2**

56 = 2*2*2*7 96 = 2*2*2*12 7 rows of 8 and 12 rows of 8
*September 2, 2014*

**Math**

6, linear, 3 -6 = -3 7, V shaped, not linear -4+2 = -2 but |-2| = +2 8, certainly not linear, infinite (undefined) at x = 2 !!! You had to ask me that ???? 2 /(6-2) = 1/2 14, same sort of problem as 8
*September 2, 2014*

**Math**

if it has x^2 in it it is certainly NOT linear !!! f(1) = 1^2 + 1 - 2
*September 2, 2014*

**Math**

hey, y = m x + b is a straight line this is y = 1 x + 5 m = 1 b = 5 if x = -2 y = -2 + 5 = 3
*September 2, 2014*

**Math**

Huh? -2 + (-5/12) -3 5/12 + 1
*September 2, 2014*

**calculus/physics**

typo, 62 lbs/ft^3
*September 2, 2014*

**calculus/physics**

I do not know what y = x10 means Whatever the function is you must find the distance from the top (y =1) down to the centroid, which is the center of mass of the water. That is the distance you have to lift the water, call it h. Then find the volume V , the area times 2 feet. ...
*September 2, 2014*

**phys urgent!**

I do not have time to run your numbers but your approach is correct. constant Vx = 2.4*10^6 cos 38 so t = .015 /Vx Vyi = 2.4*10^6 sin 38 y = Vyi t -(1/2)(qE/m) t^2 = 0 at x axis
*September 2, 2014*

**Algebra 2**

ALWAYS !!!!!!!!!!!~!~!!!!
*September 2, 2014*

**Algebra 2**

http://www.mathsisfun.com/associative-commutative-distributive.html check out associative
*September 2, 2014*

**chemistry. You did not ask a question**

They both displace the same volume and mass of water so both weights are reduced by density of water * g * volume of cube
*September 2, 2014*

**Algebra1**

5 c = -30 c = -6
*September 2, 2014*

**physics**

v = (4/3) pi r^3 dv/dr = 4 pi r^2 (which is the surface area of course :) dv = 4 pi r^2 dr dv/v = 4 pi r^2 dr/(4/3)pir^3 dv/v = 3 dr/r here dr = .04 and r = .84 so 100 * 3 dr/r = 12/.84 = 14.3 %
*September 2, 2014*

**Maths**

x and (60-x) now in six years Tom = (x+6) brother = (54-x) (x+6) = 2 (54-x) x+6 = 108 -2x 3x = 102 x = 34
*September 2, 2014*

**Finance**

http://www.mortgagecalculator.org/ pmt = principal [ r/ {1 - (1+r)^-n} ] here principal = 150,000 r = interest rate / month = .08/12 =.006666666 n = 12 * 30 = 360 months I get 1100.65 per month that calculator link also says 1100.65
*September 2, 2014*

**Maths,Physics,life science,geography,**

I assume you mean Vi = 100 m/s and a = -5 m/s^2 v = Vi + a t 0 = 100 -5 t t = 20 seconds to go from 100 to 0 at -5m/s^2 d = Vi (20) - (1/2)(5)(20)^2 d = 100 (20) - 2.5(400) = 2000 - 1000 = 1000 meters to stop, runs 200 meters beyond the end of the runway into the harbor where ...
*September 2, 2014*

**Math**

You only have three sides, usual solution does not apply 2 w + L = 750 (note not 2 L) so L = 750 - 2 w A = w L = w (750-2w) -2w^2 + 750 w = A w^2 - 375 w = -A/2 w^2 - 375 w + (375/2)^2 = -A/2 + 35156 (w-375/2)^2 = -(1/2)(A -70,312) max at w = 375/2 = 188
*September 2, 2014*

**math**

length = x width = 2000/x 2x + 2 (2000/x) = 180 x + 2000/x = 90 x^2 + 2000 = 90 x x^2 - 90 x + 2000 = 0
*September 2, 2014*

**Math**

circumference of tire = pi D = 36 pi =113 inches/revolution 55 mi/h (1 h/60min)(5280ft/mi)(12 in/ft) = 58,080 inches/min 58080 inches/min (1 rev/113 in) = 514 rev/min 514 rev/min ( 2 pi radians/rev) = 3229 radians/min
*September 2, 2014*

**Math, Calculus**

what angle has a cosine = .49 ?? cos^-1 .49 = 60.66 degrees so our answers are 60.66 degrees above and below the negative y axis (180 deg) 180 - 60.66 = 119.34 degrees 180 + 60.66 = 240.66 degrees
*September 2, 2014*

**Math**

radius = 20 height of center = 25 height = 25 + 20 sin [2 pi t/4 - pi/2} I use 2 pi t/4 because that gives 0 at t = 0 and a full revolution, 2 pi, at t = 4. I put in the phase of -pi/2 so that at t = 0 we have 25 +20 sin -pi/2 = 25 - 20 = 5 meters, the starting point at t = 0...
*September 2, 2014*

**Math**

2 A = 87-63 = 24 so A = 12 degrees average = (87+63)/2 = 75 so D = 75 + 12 sin (2 pi t/24 - p) where p is the phase to give the right temp when t = 5 when t = 5 sin (2 pi 5/24 - p) = -1 or 5 pi/12 - p = -pi/2 p = 6 pi/12 + 5 pi/12 = 11 pi/12 so D = 75 + 12 sin ( pi t/12 - 11 ...
*September 2, 2014*

**Math**

sqrt (25+49) = sqrt 74
*September 2, 2014*

**Physics, Math**

Archimedes says: volume of fluid displaced * density of fluid * g = upward buoyant force = weight is neutrally buoyant mass = weight/g = volume*density 2500 * 1.225 = 3063 kg up now subtract the mass of air in the balloon 2500 * rho what is rho, the density of air inside at ...
*September 2, 2014*

**chemistry**

Block A has a greater mass in 125 cm^3 than Block B has in 145 cm^3 so Block A is more dense.
*September 1, 2014*

**Physics**

d volume/d h = base area (draw a picture :) dv/dt = dv/dh * dh/dt so dv/dt = base area * dh/dt let rho = m/v of candy d m = dv (rho) so dv = dm/rho so (1/rho) dm/dt = base area * dh/dt or dm/dt = rho * base area * dh/dt = (m/v) * L * W * dh/dt
*September 1, 2014*

**calculus**

passenger ship east = 16 t if t</= 2 then 16 t is the answer if t >2 cargo ship north = 12 (t-2) (t>2 :) d^2 = (16t)^2 + 144(t^2 -4 t + 4) d^2 = 256 t^2 + 144 t^2 -576 t + 576 d^2 = 400 t^2 -576 t + 576 d = sqrt (400 t^2 -576 t + 576) check, yes that is 32 miles at t...
*September 1, 2014*

**physics**

h = (1/2)(9.81)(tfall)^2 h = 330 (7.8-tfall) 660 (7.8-tfall) = 9.81 tfall^2 9.81 tf^2 + 660 tf - 5148 = 0 for the positive root I get 7.06 so the sound comes up for 7.8 - 7.06 = .7407 seconds .7404*330 = 244 meters
*September 1, 2014*

**Math**

LOL any percent of 100 is that percent ! 64% of 100 is 64 75% = .75 = (3/4) (3/4)(60) = 3*15 = 45
*September 1, 2014*

**Please check my answers**

Richard is renamed "member" after the verb In the second one, you is renamed "member" after the verb.
*September 1, 2014*

**Math**

4 /(1/2) multiply top and bottom by 2 8 /(2/2) or 8 ================ (1/4) /(1/3) multiply top and bottom by 3 (3/4) / (3/3) or 3/4 ========================= (15/4) / (1/3) again top and bottom by 3 45/4 = 11 1/4
*September 1, 2014*

**Math**

You are welcome. By the way, (I am curious) could you be the same person with the blue and white socks question? It is another subject (probability) entirely on another level.
*September 1, 2014*

**Math**

9*70 + 60 = 630+60 = 690 RIGHT !!! 60/70 = 6/7 = .8571428571 which is .86 to the nearest hundredth so 9.86
*September 1, 2014*

**Check please**

animals is DIRECT (gave animals, not people:) ZOOS is in a subordinate phrase as is TIME THEM is it all right :)
*September 1, 2014*

**Engineering**

for anything pointy with straight sides v = (1/3) area of base * height here 300 = (1/3)(pi r^2) h so r^2 h = 900/pi
*September 1, 2014*

**Math**

200 above -30 is 170 above zero. Draw it on a number line.
*September 1, 2014*

**Math**

You are welcome :)
*September 1, 2014*

**Math**

not quite that easy you start with 30 socks p first blue =6/30 p second blue = 5/29 so .2*5/29 product is p2 blue p first white = 24/30 p second white = 23/29 product is p 2 white so add .2*5/29 + 24*23/(29*30)
*September 1, 2014*

**Math Proof**

You are welcome.
*September 1, 2014*

**Math Proof**

The key word here is ** EVERY ** epsilon, including one vanishingly small .
*September 1, 2014*

**Math Proof**

You say that as epsilon ---> 0, |x-y|--->0
*September 1, 2014*

**Math Proof**

yes it has to be for any old epsilon, including one that is vanishingly small so that the difference between x and y is so tiny it does not exist.
*September 1, 2014*

**Math Proof**

well epsilon is anything you want it to be, but usually you make it a small number and let it approach zero. If x = 5 and y = 7 then |x-y| = epsilon now we would call epsilon = 2 BUT x is only equal to y if |x-y|< ANY epsilon bigger than zero, including e = .0000000001 so ...
*September 1, 2014*

**Math Proof**

on second thought draw x as a point on a number line, then y points epsilon to the right and to the left. Then let epsilon ---> 0
*September 1, 2014*

**Math Proof**

well, draw two points on a number line maybe a distance epsilon apart then let epsilon go to zero.
*September 1, 2014*

**Math Proof**

LOL, well I suppose one could prove it somehow. It seems to belabor the obvious though.
*September 1, 2014*

**math**

You are welcome.
*September 1, 2014*

**math**

.2 p = 700 p =3500 .8 p = 2800 That sure is an expensive pair of shoes !
*September 1, 2014*

**physics**

call one charge Q1 and call Q2 = (200*10^-6 - Q1)
*September 1, 2014*

**physics**

E is the electric field, the force on a point charge of ONE coulomb. You can do it with E for either charge, ten multiply by the charge on the other (the target) sphere. Normally though you would just use the Coulomb law form F = k Q12Q2/r^2 see: http://teacher.nsrl.rochester....
*September 1, 2014*

**MAT222**

I answered this below.
*September 1, 2014*

**MAT222**

equation 1 2 y = x - 2 equation 2 2 y = x - 2 or both are y = (1/2) x - 1 They are both the same line. ANY old x and y that fits one fits the other.
*September 1, 2014*

**Math**

The math is much easier than the mind reading.
*September 1, 2014*

**Math**

Is that 3 n not on the right or is that the student's attempt at an answer?
*September 1, 2014*

**Math**

3 n^2 = 3 n n^2 - n = 0 n(n-1) = 0 n = 0 or n = 1
*September 1, 2014*

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