Saturday

February 6, 2016
Total # Posts: 25,123

**math**

(1/2)(3/4) = 3/8
*December 9, 2015*

**Math**

as x ---->0 tan x ---> x sin x ---> x (x - 2x) / 2x-x) = -x/+x = -1
*December 9, 2015*

**Algebra 1 help**

(4-5)/(1+2) = -1/3 yes (18-13)/(8-11) = -5/3 yes (1-y)/(10-6) = 1/4 1-y = 1 y = 0 Huh? typo? (-3-2)/0 = undefined
*December 9, 2015*

**Math**

.69 x = 1.55 x = 2.246 2.246 - 1 = 1.246 increase fraction times 100 = 124.6 % = percent increase In other words .69 is increased by 1.246(.69) =.69 + .86 =1.55
*December 9, 2015*

**MATH**

if y = 0, x = 3 so (3 , 0) if x = 0, y =-6 so (0 , -6) if x = 1, y =-4 so (1 , -4)
*December 9, 2015*

**MATH**

6 y - 15 = 4 x - 4 6 y = 4 x +11 y = (2/3) x + (11/6)
*December 9, 2015*

**Algebra**

2. (4/5) x = 10 4 x = 50 x = 12.5 ------------ check 10 - (4/5)12.5 10 - 50/5 10 - 10 0 yes
*December 9, 2015*

**Algebra**

1. 5 x - 1/3 = 4 2. (4/5) x - 3 = 7 3. r s = u - t s = (u-t)/r 4. n = q - m/p
*December 9, 2015*

**Physics**

force = rate of change of momentum F = 2 * 6/(7*10^-4)
*December 9, 2015*

**physics**

16*30 - 4*50 = 20 v
*December 9, 2015*

**Physics**

see above
*December 9, 2015*

**physics**

F = k x k = 2 g/6.1 cm 2.5g = (2g/6.1cm) x x = 6.1 (2.5/2) cm
*December 9, 2015*

**math**

15-8
*December 9, 2015*

**Pre - Cal**

origin at center of roadway, 40 meters from each end. and at height of road points (-40,20), (0,4)which is vertex, (40,20) (y -4) = k x^2 16 = k (40)^2 k = 16/1600 = .01 so y = .01 x^2 + 4 ============================== at x = 20 y = .01(400) + 4 = 8
*December 9, 2015*

**5th grade math**

40 (n-3) = 39 n 40 n - 120 = 39 n n = 120 each 39 (120) = 4680
*December 9, 2015*

**math/science**

yes, outer shell full
*December 8, 2015*

**Chemistry**

greater than because positively charged
*December 8, 2015*

**Chemistry. I got the wrong answer. Plz help**

NaCl = 23+35.5 = 58.5 g/mol so 234/58.5 = 4 mols of NaCl that requires 23 * 4 = 93 grams of Na
*December 8, 2015*

**math**

m squares lengthwise n squares width wise m/n = 4.5/3 n*m = 24 so m = 24/n 24/n / n = 4.5/3 24/n^2 = 4.5/3 n^2 = 16 n = 4 then m = 6 3 feet/4 squares = .75 feet on a side for the squares
*December 8, 2015*

**Science Help**

Helium is in the noble gas group because its outer shell is full despite having only two electrons. Therefore like the rest of that column it does not react with much of anything.
*December 8, 2015*

**Trig**

cos/(1-sin) - tan ??? cos(1+sin)/(1-sin^2) - sin/cos cos (1+sin) /cos^2 - sin/cos (1+sin)/cos - sin /cos 1/cos
*December 8, 2015*

**Math**

M = 1/24 puzzle/min H = 1/16 puzzle/min together 1/24 + 1/16 puzzle/min = 2/48 + 3/48 = 5/48 puzzle/min so 48/5 min/puzzle = 9.6 minutes
*December 8, 2015*

**Chemistry. Plz Help!**

do this the same way I did the CO2 problem
*December 8, 2015*

**Math**

2 w + 2(w+8) = 54 4 w + 16 = 54 4 w = 38
*December 8, 2015*

**Chemistry. Plz Help!**

C + O2 ---> CO2 Mols of C 20.4 /12 g/mol = 1.7 mol of C result is 1.7 mol of CO2 C = 12 O2 = 32 CO2 = 44 g/mol 1.7 mol * 44 g/mol = 74.8 grams
*December 8, 2015*

**Physics Energy**

Why would the power not be wasted in heat and compression of the ball to a great extent? In .7*10^-3 seconds the bat accelerates the ball from zero to final speed over a distance of .014 meters I assume the acceleration was constant during that time so the average speed over ...
*December 8, 2015*

**Math**

y = m x + b inverse x = m y + b y = (x-b)/m ----------------- 5 = 5 m + b or 5 m = 5 - b 5 = (5-b)/m or 5 m = 5 - b --------------------------- 5 m = 5 - b if m = 1 5 = 5 + b and b = 0 5 = (5-b)and b = 0 so f(x) = x should do (that should have been obvious :)
*December 8, 2015*

**Math**

(130/4) miles/gallon * 6 gallons = ?
*December 8, 2015*

**Math**

y = x
*December 8, 2015*

**Calculus**

in foot system g = -32 ft/s^2 Hi = 80 v = Vi - 32 t at max height v = 0 so Vi = 32 t at top so Vi = 32 * 2 = 64 ft/s h = Hi + Vi t - 16 t^2 h = 80 + 64 t - 16 t^2 h = 80 + 16 t^2 at top when
*December 8, 2015*

**Calculus AB**

Well y = 3 is continuous graph it from x = 4 to x = 7 A does it have a maximum? B does it have a minimum? C is it bigger at 7 than at 4? D is 3 equal to 18?
*December 8, 2015*

**Physics**

22.4 * 3.14 Liters
*December 8, 2015*

**Physics**

It depends on the pressure inside the car. after a few minutes the car will fill with water from holes in the floor etc and only a bubble of air at ambient (water) pressure will remain under the roof (avoid leaky sun roof). At that point the door (or window) will open easily.
*December 8, 2015*

**Physics**

Enough already, what did you get?
*December 8, 2015*

**Spanish**

LOL - name is the same in US pharmacies. It is not the cat stuff.
*December 8, 2015*

**Calculus**

Let me get this right - you want me to square all these differences to save you the trouble of doing it. I already took the course. Let us see what you did.
*December 8, 2015*

**physics**

F = m a constant F constant m so constant a
*December 8, 2015*

**math**

8/225 = 2 pi r/360 :)
*December 8, 2015*

**Science**

I thought I did. Read what I write carefully.
*December 8, 2015*

**Science**

1. agree height is twice amplitude and wavelength is distance between crests 7. agree but actually not really. The frequency did not really change, only the frequency you hear changed due to Doppler effect. 9. agree. yes, sonar sends out a pulse of sound and sees how long it ...
*December 8, 2015*

**Physics**

I assume hands under shoulders x = CG to feet hands hold 268*2 = 536 N so 536 * 1.36 = 750 x x = .972 m from CG to feet 1.36 - .972 = .388 CG to hands (shoulders)
*December 8, 2015*

**Mathxxx!!!**

before I respond I would like to see your attempts. By the way if you can solve for x, there is a solution. If it is impossible to solve, there is no solution. So tell me what x is in problems one (a tricky one) and two. if you have 5 x and only 5 x on one side and 5 x and ...
*December 8, 2015*

**math**

yes
*December 8, 2015*

**College Physics**

nobody knows because you did not give me: specific heat of ice heat of fusion of water specific heat of water heat of vaporization of water Cp of steam Energy = 10 grams (or .010 kg if using kg) times the sum of: [5 deg * spec heat ice + heat of fusion of water + 100 deg * ...
*December 8, 2015*

**Physics**

300 rev/min (2 pi radians/rev)(1 min/60s) =31.4 radians/second 31.4 rad/s * 1 m = 31.4 meters/second
*December 8, 2015*

**Physics**

another way (easier) The force F times 5 meters = potential energy lost in water = m g (height above water) note no pe change below water because buoyancy is about the same as weight 5 F = 45 * 9.81 * 8 F = 706 Newtons
*December 8, 2015*

**Physics**

well, there is a rick you can use here to make it easy. If the force is constant, then the average speed is halfway between the starting speed and the final speed (which is zero here. So what is the speed when he hits the water? v final = sqrt (2 g h) =sqrt(2*9.81 * 8) = 12.5 ...
*December 8, 2015*

**Physics**

ke = (1/2) m v^2 goes until that energy is stored in spring so (1/2) m v^2 = (1/2) k x^2
*December 7, 2015*

**Physics**

kinetic energy coming to the jump = (1/2) m(121) kinetic energy at the top = (1/2) m (1) loss of Ke = (1/2) m (120) = gain of potential = m g h (note that the mass is irrelevant, big person goes as high as small one if same speeds) so (1/2)(120) = 9.81 h solve for h
*December 7, 2015*

**math**

4.44 is the biggest
*December 7, 2015*

**whoops**

yes, you need that -1 at the end
*December 7, 2015*

**Typo**

3 cos (x/2 - pi/4) That is very close to what you have except for that strange -1 at the end.
*December 7, 2015*

**Math please help**

well it ranges from -4 to +2 -4 to 2 = 6 so you are right the amplitude is 3 y = 3 cos (a x - phi) when x = pi/2 , cos (a x - phi) = 1 so a pi/2 - phi = 0 because cos 0 = 1 when x = 5 pi/2, cos ( a x- phi) = -1 so a 5 pi/2 - phi = pi, because cos pi = -1 so we have two ...
*December 7, 2015*

**Physics Help**

Re is distance from earth center first checking your paragraph force on each = F = G m ME /Re^2 dF/dr = -G m ME 2 Re / Re^4 = - 2 G m ME/Re^3 so if dr = 2a then dF = -4 G m ME a/Re^3 agree Hey, surely you mean mass = ρ(4/3) pi a^3 !!!!!!!!! Mutual Force = G m^2 /(2a)^2 = ...
*December 7, 2015*

**Physics**

2.96*10^-5 /(.0028/4) = .0423 m^3/s
*December 6, 2015*

**Physics**

try 4 times that :)
*December 6, 2015*

**Physics**

A=3.14*0.03^2=.0028 !!!!!!!!!!!!!!!!!!! .03 is DIAMETER NOT Radius you want A = pi D^2/4 otherwise you have the right idea
*December 6, 2015*

**math**

sin 5 x = 0 well, zero and every time 5 x is a multiple of 180 if x = 0 , sin 5 x = 0 if x = 180/5 = 36, sin 5 x = 0 if x = 360/5 = 72 in fact for any multiple of 36 until we reach 9 9 * 36 = 324 and sure enough sin 5*324 = sin 1620 = 0
*December 6, 2015*

**Math**

y = 3 x invert x = 3 y y = x/3 sure enough you got it :)
*December 6, 2015*

**8th Grade pre Algebra : HELP!**

0.123123123... 123/10^3 + 123/10^6 + 123 /10^9 ..... = (123/1000)(1 + 10^3 + 10^3*10^3 + 10*3*10*1*10^3 ...... = (123/1000) (a + ar + 1 r^2 ..... a = 1 r = 1/1000 is infinite geometric series sum = 1/(1-r) so =(123/1000)(1/(1-1/1000) = 123/1000 (1/999/1000) =123/999 try 123/...
*December 6, 2015*

**8th Grade pre Algebra : HELP!**

question 9 Do you know how to convert a REPEATING non-terminating decimal into a quotient of whole numbers.
*December 6, 2015*

**8th Grade pre Algebra : HELP!**

Question 5 I do not understand - typo?
*December 6, 2015*

**8th Grade pre Algebra : HELP!**

First try yourself. Post what you did. The first couple I am sure you can do. like what is 5 * 5 * 5 and what is the square root of (5*5) /(8*8)
*December 6, 2015*

**Applied Calc**

Get it ?
*December 6, 2015*

**Applied Calc**

Otherwise I am agreeing with Wolfram
*December 6, 2015*

**Applied Calc**

whoop, that is 3 x^5 not 4 x^5
*December 6, 2015*

**Applied Calc**

(1-x)^6 = 1 - 6x + 15x^2 - 20x^3 etc multiply by x^2 so x^2 - 6x^3 + 15x^4-20x^5 .....etc THEN integrate (1/3)x^3 - (3/2)x^4 + 4x^5 -(10/3)x^6 ... etc
*December 6, 2015*

**Applied Calc**

The only thing I know to do is multiply (1-x)^6 out (use binary coefficients) then you have a whole string of simple ones which is why the answer at Wolfram starts with someting times x^9
*December 6, 2015*

**Applied Calc**

go to http://www.wolframalpha.com/input/?i=integrate+x%2F%281-x%29 type in: integrate x^2(1-x)^6 It is a serious mess !!!
*December 6, 2015*

**math**

f' = -2x e^(1-x^2) zero when x = 0 f" = -2x (-2x e^(1-x^2)) -2 e^(1-x^2) = (4 x^2 -2)e^(1-x^2) when is that negative ? e^whatever always + so when 2 (2x^2-1) is negative x^2 always + when x^2 <1/2 -1/sqrt 2 < x <1/sqrt 2 ?
*December 6, 2015*

**Math**

y = (-2) x
*December 6, 2015*

**Applied Calc ah !**

now go to http://www.wolframalpha.com/input/?i=integrate+x%2F%281-x%29
*December 6, 2015*

**Applied Calc ah !**

well, first multiply top and bottom by (1 - sqrt x) (1-sqrt x)^2 ------------ dx 1 - x (1- 2 sqrt x )^2 ------------ dx 1 - x dx/(1-x) - 2 x^.5 dx/(1-x) + 4 x dx/(1-x)
*December 6, 2015*

**algebra**

7 + 4/4 - (3 + 1/4) = 7 - 3 + 4/4-1/4 = 4 + 3/4 = 4 3/4 =============== check 3 1/4 + 4 3/4 = 7 4/4 = 8 whew!
*December 6, 2015*

**physics**

she loses potential energy as she falls and gains speed (kinetic energy) m g h = -70 * 10 * 2.5 Joules
*December 6, 2015*

**mnps**

2.4 m + 2.6 m = 5 m 10 - 5 = 5 m left
*December 6, 2015*

**Algebra 1, Physics**

for Muriel height at x = 10: y = - (9.8/14^2) (100) + 10 + 2 y = -5+12 = 7 meters high for Connie height at x = 10 y = -(9.8/16^2)100 + 10 + 2 = -3.8 +10 + 2 = 8.2 m high 7 meters is about 21 feet. That is not very high but will do 1 story with a slightly pitched roof.
*December 6, 2015*

**calculus**

if you are using our moon and are close to it, g = (1/6) g earth approximately I am not sure we can make those assumptions.
*December 5, 2015*

**calculus**

This could only be an MITx problem I left there in 1959 so this will only be a rough attempt. NOTE - I am using h, the height for above surface and d for total distance from center. We want f(h) first Moon center at C d = r + h distance from center of moon at P when at P, how ...
*December 5, 2015*

**physics**

I did the hard part. I assume you can do the both at the same time part.
*December 5, 2015*

**Hey, check and see if I have already done it before posting again**

http://www.jiskha.com/display.cgi?id=1449357347
*December 5, 2015*

**physics**

Ah, I just did this about an hour ago.
*December 5, 2015*

**gifted ELA**

If I did English and not physics I would strike for more pay.
*December 5, 2015*

**physics**

Weight number 1: 48 + 8 + 19.5 = 75.5 kg on the wagon 19.5 kg back at 9 relative to ground and girl so 75.5 u = 19.5 * 9 u = 2.325 forward now weight number 2 before throw: momentum = 75.5 * 2.325 = 175.5 relative to ground after throw missile momentum back relative to ground...
*December 5, 2015*

**no way - typo?**

on what planet is 1 atm = 2 atm ?
*December 5, 2015*

**Physics/Science**

delta T = 30 - 420 = - 390 delta t = 50 min so -390/50 = 7.8 degrees per minute
*December 5, 2015*

**Math Nunbers**

call it A*100 + B*10 + C then we know A + B + C = 19 B + 4 = 2 A C*100 + B*10 + A + 99 = A*100 + B*10 + C now plug and chug
*December 5, 2015*

**Physics**

well, we have .035 kg of ice at -14 we have .4 kg of water at 0 If those really are the numbers, the answer is that some of the water gets frozen by the ice which is 14 degrees BELOW freezing. At least 35 grams of ice will be left. How much water can we freeze? How much heat ...
*December 5, 2015*

**Statistics**

I get .5393
*December 5, 2015*

**Statistics**

100 trials probability of success = .9 probability of failure = .1 we need P(86) P(87) P(88) etc down to P(91) This is a binary distribution problem Then add them all I will do one of them P(86) = 100C86 * .9^86 * .1^(100-86) 100C86 = 100! /[ 86!(14...
*December 5, 2015*

**Chemistry (Gas)**

Yes, assume 1 atm and around 0 to 20 C the water would be frozen at 0 (unless salt :) and is probably not much more than 20 that range is small compared to 273 so close enough for your scuba tank calculation.
*December 5, 2015*

**algebra**

192 = 112 t - 16 t^2 or 16 t^2 - 112 t + 192 = 0 t = [ 112 +/- sqrt ( 12544 - 12288)]/32 t = [112 +/- 16 ]/ 32 t = 3 seconds on the way up and t = 4 seconds on the way down
*December 5, 2015*

**hj**

mary + 3 mary = 480 4 mary = 480 mary = 120
*December 5, 2015*

**Physics/Science**

17 degrees in 45 minutes = 17/45 = .378 degrees/minute
*December 5, 2015*

**science**

Well, Silver Sulfate is relatively insoluble and I suspect it is the precipitate. Calcium Nitrate is soluble.
*December 5, 2015*

**Calculus**

I have a hunch that f is in MILLIONS f(t)= (1/2)(1.498) t^2 + 1.626 t + c to find c put in year 2 8.893 = (1/2)(1.498) (4) + 1.626 (2) + c
*December 5, 2015*

**science**

Well, it is certainly not from over on the right there where the Halogens live. Since Cl is a halogen, group 7 which is missing an electron in the outer shell and wants to grab one to become a Cl-1 ion, we really want something with an extra electron easily removed. That means...
*December 5, 2015*

**Algebra**

You are welcome.
*December 5, 2015*

**Algebra**

jordan worked n maria worked (8/5) n (8/5) n - n = 15 8 n - 5 n = 75 n = 25 (8/5)n = 40
*December 5, 2015*

**social studies? i think idk**

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=14&cad=rja&uact=8&ved=0ahUKEwjr5422qMXJAhVFmh4KHW3bBoQQFghdMA0&url=http%3A%2F%2Fhenryfordchangingtpm.weebly.com%2Feconomic-impact.html&usg=AFQjCNHncn7Vo0UvgMcMiqaThUZeGZh_rA&sig2=6FSowIEVir_5jW55Bu1m4Q
*December 5, 2015*