Thursday

August 28, 2014

August 28, 2014

Total # Posts: 18,115

**AP Calc. AB**

d/dx (1/8) x^3 = (1/8) d/dx x^3 = (1/8) (3 x^2) = (3/8) x^2 when x = 4 = (3/8)(16) = 6
*August 27, 2014*

**physics**

a = F/m = - 50/20 = -2.5 v = Vi + a t 0 = 15 - 2.5 t t = 15/2.5
*August 27, 2014*

**Maths**

2875,35 - 2010,50
*August 27, 2014*

**Algebra**

I suppose that is true. Open y = 7 - 3 Closed 4 = 7 - 3
*August 27, 2014*

**Science**

A leg, by any other name, is still a leg.
*August 27, 2014*

**physics**

take 40 away from 200
*August 27, 2014*

**algeba**

Then multiply by P Q so far BP (not the oil spill company) + BQ = PQ B (P+Q) = PQ one more step and you are home
*August 27, 2014*

**algeba**

multiply everything both sides by B
*August 27, 2014*

**Math**

Sin A/a = sin B/b = sin C/c
*August 27, 2014*

**maths**

120
*August 27, 2014*

**Physics**

I can say noting about velocity because all I have is speed. For velocity direction is also required. For speed you can use a speedometer. For velocity you need both a speedometer and a compass.
*August 27, 2014*

**algebra**

21/7 + 3(36) 3 + 108 111
*August 26, 2014*

**Algebra**

LOL , eight crackers per serving * 12 servings = 96 indeed
*August 26, 2014*

**physics**

Sorry, I made that too hard. the two unknown vectors result in a vector that is equal and opposite to the first one so B + C is 136 units 35 deg south of east |B|^2 + |C|^2 = 136 ^2 Bx + Cx = 136 cos 35 By + Cy = -136 sin 35 Bx = |B| sin 69 By = |B| cos 69 Cx = -|C| sin 19 Cy...
*August 26, 2014*

**physics**

add up the north components (y axis) add up the east components (x axis) take the square root of the sum of the squares for the magnitude Tan theta = total y/total x but that theta is the math theta, counterclockwise from x axis for compass angle -- > 90 - theta
*August 26, 2014*

**math**

LOL, more MITx ?
*August 26, 2014*

**math**

distributive property (3x-2)(4x-3y) if you find that easier
*August 26, 2014*

**math**

remember (a^2 - b^2 ) = (a-b)(a+b)
*August 26, 2014*

**math**

(.2*12.5 -.02*12.5)/(.05 *.2) (.2*12.5 - .2*1.25 ) / (.05*.2) (12.5 - 1.25) / .05 1125 /5 225
*August 26, 2014*

**Geometry**

You are welcome :)
*August 26, 2014*

**Geometry**

I drew a diagram which I can not reproduce here A--------------------------------C --------------------B on top line A ---------------D ------16------C A ---------------D --------------------H A-------E --------D A ------E ---F ---D A-------E -G-F
*August 26, 2014*

**Geometry**

First find AG AD = 16 AE = 8 and EF = 4 so EG = 2 AE + EG = AG = 8 + 2 = 10 Now find AH AD = 16 AB = 64 so DB =64 - 16 = 48 half of that is 24 so AH = 16+24 = 40 GH = AH-AG = 40 - 10 = 30
*August 26, 2014*

**Math**

155.09 + 5.77
*August 26, 2014*

**math**

sketch it first angle from x axis = tan^-1 (8/6) = 53.1 deg so first clockwise 60 degrees so -6.87 degrees (in quadrant 4) tan -6.67 = -.12 so if x = 1, y = -.12 now we want that to be a unit vector so find magnitude of what we have r = sqrt(x^2 + y^2) = sqrt 1.014 = 1.007 so...
*August 26, 2014*

**Calculus**

Hi = 500 Vi = +14 v = Vi - 9.8 t v = 14 - 9.8 t at top, v = 0 so at top t = 14/9.8 h = Hi + Vi t - (9.8/2) t^2 so for example max height is h = 500+14 (14/9.8)-(9.8/2)(14^2)/9.8^2 or h = 500 + (1/2)(14^2)/9.8 at top
*August 26, 2014*

**physics**

it is precise it is NOT accurate 455 is NOT 500
*August 26, 2014*

**physics**

precise but not very accurate (i think its this one) yes, values close together but wrong
*August 26, 2014*

**physics**

We can not see your list. I would say wrong :)
*August 26, 2014*

**Physics**

v = Vinitial + a t if a is constant so of course no acceleration = change in velocity /change in time
*August 26, 2014*

**compound interest**

200 *1.2^3 + 200*1.2^2 + 200*1.2
*August 26, 2014*

**Science**

well, I would pick a) if length were spelled correctly. Farenheit is not SI weight is force, gram is mass meniscus is shape of the surface in a barometer or thermometer
*August 26, 2014*

**math**

I can not write TODAY because it was Yesterday :(
*August 26, 2014*

**Physics**

That depends what direction you define as positive. If + is direction from your house out, then a is positive leaving and negative as you decelerate (brake) to land at your destination. However as you start home, if you do not redefine the positive direction, your increase in ...
*August 26, 2014*

**Physics**

You are welcome.
*August 26, 2014*

**Physics**

The acceleration remains constant one g down as the speed up drops to zero at the top of the flight and then it starts downward hitting the ground at the same speed down it started up but the opposite direction.
*August 26, 2014*

**physics**

F = m a = 18 * 3 N
*August 26, 2014*

**Physics MITx? ME course 2 ?**

Looks like a course 2 MITx problem to me. You are on your own.
*August 26, 2014*

**Math**

You just did.
*August 26, 2014*

**geometry**

Draw a good sketch and make the incident and reflected rays at the same angle to the perpendicular to the mirror at the bottom.
*August 26, 2014*

**chemistry**

C6H6 --> 6*12 + 6 = 78 grams/mol so we have 1/78 mol 1/78 mol in 0.1 liter --> 10/78 molarity etc
*August 26, 2014*

**Physics - figure with angles?**

If you tried to copy and paste it, that does not work here.
*August 25, 2014*

**Math**

green on first try = 1/4 green on second try: red first = 3/4 then green = 1/3 so 3/4 * 1/3 = 1/4 green on third try red first = 3/4 red second = 2/3 green third = 1/2 3/4 * 2/3 * 1/2 = 1/4 green o fourth try red first = 3/4 red second = 2/3 red third = 1/2 green fourth = 1/1 ...
*August 25, 2014*

**Calculus-Math**

well, we know we keep the 4 :) Let z = 4(sec u)^7 and u = pi t - 6 then dz/du = 4 * 7 (sec u)^6 d sec u/du = 28 (sec u)^6 (sec u )(tan u) = 28 sec^7 u tan u dz/dt = dz/du * du/dt = dz/du * pi so dz/dt = 28 pi sec^7(pi t-6)tan(pi t-6)
*August 25, 2014*

**French**

Pourriez-vous traduire ces expressions pour moi ?
*August 25, 2014*

**9th Grade Bio**

In "respiration" by the way you are basically oxidizing organic molecules using O2 from the air, sort of like burning wood to produce energy and CO2 but at much lower temperature :) At least that is the way a physicist as opposed to a biologist sees it.
*August 25, 2014*

**9th Grade Bio**

You are welcome.
*August 25, 2014*

**9th Grade Bio**

https://www.google.com/search?q=respiration+definition&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a&channel=sb
*August 25, 2014*

**Math**

y = (4/3) x - 6 3 x = 7 - (4/3)x + 6 9 x = 21 - 4 x + 18 13 x = 39 x = 3 then y = (4/3)(3) - 6 y = -2
*August 25, 2014*

**Algebra**

No, when you list ordered pair as (a,b) a is independent variable x and b is dependent variable y
*August 25, 2014*

**Algebra**

try using 0 for x and 3 for y 3 = 0 + 3 sure enough
*August 25, 2014*

**math**

10^3 * 10^3 = 10^6 = one million
*August 25, 2014*

**Algebra**

2 x^2 = 108 x^2 = 54 note: 54 = 6 * 9 = 6 * 3^2 so x = 3 sqrt 6 or x = -3 sqrt 6
*August 25, 2014*

**chem**

the gas is still about 80% N2 so 8 atm It would also be 2 atm O2 instead of 0.20 atm O2 or ten times the O2 pressure. Both the high partial pressure of N2 and of O2 cause problems for divers and for deep diving for extended times mixtures with lower O2 content and Helium ...
*August 25, 2014*

**algebra**

draw a number line put a dot at +7 go left negative one when you go left negative, you go right
*August 25, 2014*

**math**

four choices for the first three for the second two for the third one for the fourth 4*3*2*1 = 24 usually this is called permutations and is written as n! where n! = n * (n-1) * (n-2) ....*1
*August 25, 2014*

**Agebra**

you did
*August 25, 2014*

**Physical Science**

LOL You only have two significant figures in 3.0 365.25 * 3.0 = 1095.75 which to two sig figs is 11*10^2
*August 25, 2014*

**Physical Science**

100 * .2/37 100 * .3/37
*August 25, 2014*

**geography**

because it is big and you only see a tiny bit of the surface of the sphere because you are so close to the surface like an ant on a huge round balloon. If you get far away, like in an orbiting space station, you can see the curvature.
*August 25, 2014*

**business math**

markup = 25,869.57 - 11,900 = 13,969.57 13,969.57 * 100 / 25,869.57 = 54
*August 25, 2014*

**phychics**

Moreover for the sake of us physicists, please spell physics.
*August 25, 2014*

**phychics - typos**

what is the friction on this friction track you gave the speed at the top - why do you ask for it? If it is another hill, what is the height?
*August 25, 2014*

**Physical Science**

I do not know because I do not know the true value. However I can give the percentage range from the average of the two. (37.2+36.7)/2 = 36.95 difference = +/- 0.25 100* .25/36.95 = + or - .68%
*August 25, 2014*

**Ed Tech**

I have a sneaking suspicion that they want antivirus software if they are downloading stuff.
*August 25, 2014*

**Math**

The round one with red and blue and white stripes
*August 25, 2014*

**Calculus**

p = 2L + 2 w w = 64/L so p = 2L +128/L w can range from 0 to L if w = 0, L ---->oo and p -->oo if w = L, L = w =8 and p = 4*8 = 32 so 32 </= p </= oo
*August 25, 2014*

**Math**

I suspect you mean but did not type: 5x^7/(97x+9) and not (5x^7/97x)+9 which is too easy If my guess is right and your use of order of operations and parentheses is wrong then use (bottom derivative top - top derivative bottom )/ bottom^2 [(97x+9)35x^6 - 5x^7((97)]/(97x+9)^2...
*August 25, 2014*

**Calculus**

Kadudu, see where you posted below
*August 25, 2014*

**Calculus**

sin 2x = 2 sin x cos x so 6 sin x cos x = 3 cos x right off, if cos x = 0, we have solutions. That is when x = pi/2 and x = 3 pi/2 also when sin x=1/2 that is x = pi/6 and x = 5 pi/6
*August 25, 2014*

**Physics**

I suspect you mean meters not miles but whatever s = speed horizontal: u = s cos 30 = .866 s if t = time rising, then 2t = time in air 15,000 = u *2 t = 1.732 s t so s t = 8660 vertical Vi = s sin 30 = .5 s v = Vi - 9.81 t v = 0 at t (the top) 0 = .5s - 9.81 t t = .05096 s so ...
*August 25, 2014*

**Physics**

If it takes 5 seconds to cover that distance you will have to throw it just about straight up so it will stay up five seconds ! u = constant horizontal speed = 10m/5s = 2 meters/second in 5 seconds it goes up 3 meters 3 = Vi t - 4.9 t^2 3 = Vi(5) = 4.9(25) 3 = 5 Vi - 122.5 Vi...
*August 25, 2014*

**physics**

You can not think of any at all?
*August 25, 2014*

**Math**

A 1/15 wall / day B 1/20 wall / day together 1/15 + 1/20 = 7/60 wall/day times 4 days = 28/60 = 7/15 wall
*August 24, 2014*

**Math**

been there, done that Masood + 1.2 Masood = 550 2.2 Masood = 550 masood = 250
*August 24, 2014*

**I think Chemistry**

Sorry, can not help
*August 24, 2014*

**math**

area of base = pi r^2 = 35^2 pi volume = height*base area = 50 * 35^2 pi ft^3 gallons = 50 * 35^2 * pi * 7.5
*August 24, 2014*

**PHY SCI**

Ac = v^2/R R = 500 meters v = 90 km/h * 1000 meters/km * 1 hr/3600 s
*August 24, 2014*

**PHY SCI**

Oh my, I suppose I will use feet and inches and miles and pounds and g = 32 ft/s^2 s = speed in ft/s u = horizontal speed = s cos 42 = .743 s Vi = s sin 42 = .669 s t = time rising 2 t = time in air 300 feet = 2u t = 1.49 s t v = Vi - 32 t 0 = .669 s - 32 t t = .0209 s so 300...
*August 24, 2014*

**Math**

7/15
*August 24, 2014*

**physics**

I am going to make a lot of symmetry assumptions and assume these are hockey puck with no rotational energy initial: V = vx i call ball mass = 1 kg momentum = vx i energy = .5 vx^2 Final ball 1 V1 = V1x i assuming symmetry so V1y = 0 momentum = V1x i energy = .5 Vix^2 ball 2 ...
*August 24, 2014*

**hurestics**

b+t = 74 3 t - 2 b = 87 3(74-b) -2b = 87 222 - 3 b - 2b = 87 5 b = 135 b = 27
*August 24, 2014*

**hurestics**

he had 27 available he spent 2 on 2 pencils so they were a dollar each
*August 24, 2014*

**MATHS LAH**

42 + 4 7(6) + 4(1)
*August 24, 2014*

**Calculus**

3 d/dx sin (4x) note: d/dx sin u = cos u * du/dx 3 cos (4x) * d/dx (4x) 3 cos (4x) * 4 12 cos(4x)
*August 24, 2014*

**Phsical Science**

The only real reason to stick with it in the US is the cost of conversion: http://education-portal.com/academy/lesson/english-system-of-measurement-definition-history-advantages-disadvantages.html#lesson
*August 23, 2014*

**Algebra**

I gather you mean: (2x+3)/4 or 2 x + 3 --------- 4 If so, yes
*August 23, 2014*

**chemistry**

MgCl2 HUH? Mg is +2 and Cl is -1
*August 23, 2014*

**Algebra**

yes, that is just a reversal of order which is commutative. It will work until you get to matrix multiplication.
*August 23, 2014*

**Algebra**

agree
*August 23, 2014*

**American Government**

You are welcome. I think on the average over the range of issues the bar has more influence. I personally resent all of these organizations and their influence.
*August 23, 2014*

**American Government**

I decline to give my opinion because I consider it embarrassing.
*August 23, 2014*

**chemistry**

you only have one H2O on the sulfate so I would call it a monohydrate Are you sure it is not 7H2O ???? instead of /H2O ???? the would make it D
*August 23, 2014*

**chemistry**

B is wildly wrong !!! C is also Wildly wrong for the same reason. Hydrogen reacts. Helium reacts with essentially nothing because that first level is full of its two electrons D is just crazy. Helium is our second element with two protons and two electrons.
*August 23, 2014*

**chemistry**

mass does not change in a chemical reaction
*August 23, 2014*

**Government**

You are welcome :)
*August 23, 2014*

**Government**

http://www.washingtonpost.com/wp-dyn/content/article/2009/07/05/AR2009070502770.html
*August 23, 2014*

**Physics**

does not matter what the charge on B is, call it -1 and call k = 1 To the left 2/(1)^2 + 1/(1)^2 = 3/1 to the left so we need 3 to the right Qd/4^2 = 3 Qd = 16*3 = 48
*August 23, 2014*

**College Algebra 1**

10 x^2 - 41 x + 21 = 0 (5 3) (2 7) ??? yes, 6 and 35 (5x-3)(2x-7) = 0 x = 3/5 or x = 7/2
*August 23, 2014*

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