Monday

May 2, 2016
Total # Posts: 26,149

**Math Exponetial Function Problem Question?**

You multiply the 27 by the amplitude, not the log of the amplitude. then take the log of the new bigger amplitude for the new Richter number.
*January 2, 2016*

**Math Exponetial Function Problem Question?**

No, log scale I answered this yesterday http://www.jiskha.com/display.cgi?id=1451681946
*January 2, 2016*

**Spanish**

whew :)
*January 2, 2016*

**Math**

I did this not long ago http://www.jiskha.com/display.cgi?id=1451681946
*January 2, 2016*

**Math**

hint here: http://www.jiskha.com/display.cgi?id=1451675195
*January 2, 2016*

**Math**

You are welcome.
*January 2, 2016*

**Math**

Suspect you mean 2^(2x+3) = 80 that means (2x+3)log 2 = log 80 (2x+3) = 6.32192 2x = 3.32192 x = 1.6609
*January 2, 2016*

**Math**

19 * 100 / 27 = 70 % is his score in percent. I do not know if you are using letter grades or whatever.
*January 2, 2016*

**Math**

I think your answer is fine. So is the 3^2 = 9 one.
*January 2, 2016*

**Math**

well 9^x = 3^(2x) so log^-1 (2 x log 3) is a perfectly good answer. So is Log^-1(xlog(9)) They are the same :)
*January 2, 2016*

**Math**

Yes, but count brackets. I try to use different ones log^-1[ x(log 7 - log 8) ]
*January 2, 2016*

**Calculus**

It is just that sqrt (a^2-b^2) is not a - b
*January 2, 2016*

**Calculus**

By the way, you tried x^3 as well :..... sqrt (1-x^6) into 1^(1/2)- x^(3) ..."
*January 2, 2016*

**Calculus**

Why should I not let u = anything I choose ? LOL I see an x^6 and an x^2 so I tried x^3
*January 2, 2016*

**Calculus**

sin^-1 u + c so sin^-1 x^3 + c
*January 2, 2016*

**Calculus**

sqrt (1-x^6) into 1^(1/2)- x^(3) I do not think so I will try the easy way u = x^3 du = 3 x^2 dx so I have du/ sqrt (1-u^2)
*January 2, 2016*

**Calculus**

B and D
*January 2, 2016*

**Calculus**

In C, that nasty x cancels
*January 2, 2016*

**Calculus**

the problem with B and D is that dx = dy/f(x) so the substitution does not get rid of the x
*January 2, 2016*

**Calculus**

I had trouble with B and D
*January 2, 2016*

**Calculus**

∫√(x^2-1) dx <---- NOTE that dx let y = x^2-1 then dy = 2 x dx so dx = dy/2x ∫√(x^2-1) DX =∫y^.5 dy/2x a mess again
*January 2, 2016*

**Calculus**

You are wrong. A CAN easily be solved Be sure to include the dx in your integrals so you include it when you substitute
*January 2, 2016*

**Calculus**

B. let y = 1 - x^2 dy = -2 x dx ∫1/√(1-x^2) dx = ∫y^-.5 dy/(-2x) very awkward Hey be sure to include the dx in your integrals C will be easy because the x in -2xdx cancels
*January 2, 2016*

**Calculus**

A. let y = x-1 dy = dx ∫√(x-1) = ∫y^.5 dy that works
*January 2, 2016*

**Calculus**

You are welcome.
*January 2, 2016*

**Calculus**

∫(x^3-x^2) dx/x^2 =∫(x^3/x^2-x^2/x^2)dx = ∫(x^3/x^2-x^2/x^2)dx = ∫(x-1)dx = (x^2/2) - x + c which is the fourth option and is also what you got
*January 2, 2016*

**spanish**

If you are not sure and you are taking Spanish, we have a serious problem here :)
*January 2, 2016*

**spanish**

Lives in a hotel and is rich and spends much money Does not respect Mexicans or appreciate their clothes. But, interestingly Peace Corps volunteers must come from a different country entirely :)
*January 2, 2016*

**World Civilizations**

Of course there was introducing the natives to Christianity. I do not think I will follow that train of thought further and have deleted a sentence or two.
*January 2, 2016*

**Physics of ice skating**

Well, I guess the skate you are pushing with is at an angle so the long sharp edge can get a grip on the ice while the forward skate moves forward straight ahead. I had never thought about it but that is the way you skate although 45 degrees seems kind of extreme. If you look ...
*January 2, 2016*

**Hmm, I can not help**

... but if you do get help, let me know. We have three dogs that desperately need training. Luckily they are tiny.
*January 2, 2016*

**clickable link I hope**

http://en.wikipedia.org/wiki/Pacific_Route
*January 2, 2016*

**Social Studies (Check, Please!)**

I might go a bit further and claim that Russia would have collapsed without the convoys to Murmansk and to their Pacific seaport Vladivostok. https://en.wikipedia.org/wiki/Pacific_Route
*January 2, 2016*

**Math**

c * 11.5 + p * 13 = 1255 c + p = 100
*January 2, 2016*

**math**

You are welcome.
*January 2, 2016*

**math**

For example: Boole was appointed to the chair of mathematics at Queens College, Cork in 1849. In fact he made an application for a chair in any of the new Queen's Colleges of Ireland in 1846 and in September of that year De Morgan, Kelland, Cayley, and Thomson were among ...
*January 2, 2016*

**math**

http://www-history.mcs.st-andrews.ac.uk/Biographies/Boole.html
*January 2, 2016*

**Math**

No problem. You are welcome.
*January 2, 2016*

**Math**

Angle at C is common to triangles ACD and to ACB since angles in both triangles add to 180, angle ADC = twice angle ABD call angle CAD = T then BAD = T call angle ABD = A then angle ADC = 2A then sin T / 6 = sin 2A /x sin 2T / 11 = sin A /x sin T / 5 = sin (180-2A)/8 = sin 2A...
*January 2, 2016*

**Physics**

I did this a few days ago. http://www.jiskha.com/display.cgi?id=1451329598
*January 2, 2016*

**maths**

3/4*1/3 = 1/4
*January 2, 2016*

**Calculus help plz**

Thanks for figuring out what was meant. I just threw up my hands in frustration.
*January 2, 2016*

**Calculus**

Happy to help :)
*January 2, 2016*

**Calculus Huh??**

Is this supposed to be: ∫((cos^3(x)/(1-sin^2(x)) dx ?? 1 - sin^2 x = cos^2 x because cos^2 x + sin^2 x = 1 so you have ∫ cos(x) dx the derivative of the integral is what you already have, cos x the integral is sin x + c
*January 2, 2016*

**Physics**

m g = 2890 m g - 2200 = m (.36) You did not say what your question is but you can solve that for m and for the local g
*January 2, 2016*

**Math**

depends what you mean by intense. If amplitude is 27 times log A = 3.2 so A =1584 B = 1584 * 27 = 42792 log B = 4.63
*January 1, 2016*

**mechanics**

You are asking me to write a chapter in your text book. Any physics text can help you better than I can. for the first question: F = G Me m/r^2 = (GMe/r^2) m for changes in r that are small compared to earth radius, like from here to the top of Mt Everest this quantity is ...
*January 1, 2016*

**physics**

40 cycles / (8*60 seconds) = .083 Hz
*January 1, 2016*

**Physics**

How long to fall 46-1.8 = 44.2 meters ? 44.2 = (1/2) g t^2 t = sqrt (88.4/9.81) t = 3 seconds d = u t = 1.20 * 3 = 3.6 meters
*January 1, 2016*

**Reposting calculus help plz**

y dy = x dx + x^3 dx y^2/2 = x^2/2 + x^4/4 + c
*January 1, 2016*

**mechanics**

torque = moment of inertia * angular acceleration 40 * 0.20 = 30 alpha alpha = .267 radians/sec^2 omega = alpha * t omega= .267 * 4 = 1.07 radians/sec angle = (1/2) alpha *t^2 = .5 *.267 *16 = 2.136 radians divide by 2 pi = .34 revolutions torque * angle = work in = 8 * 8.53...
*January 1, 2016*

**Maths**

assume you mean 24 m not cm distance d from tree tan 45 = (24-h)/d tan 60 = h/d so (24-h)/tan 45 = h/tan 60
*January 1, 2016*

**Maths/physics need help agn**

up force from each student = 81 N = F cos 60 = F/2 so 162 N
*January 1, 2016*

**Maths/physics**

(1/2) m v^2 = (1/2) k x^2 .5 (1600) = .5 k (.04) k = 40,000 Newtons/meter F = k x = 40,000 (.2) = 8000 N
*January 1, 2016*

**maths**

area of brick = .25*.12 = .03 m^2 area of yard = 20*30 = 600 m^2 number of bricks = 600/.03 = 20,000
*January 1, 2016*

**Math parentheses ?**

do you mean 3 - x = sqrt (x^2 - 5) ?? if so 9 - 6 x + x^2 = x^2 - 5 6 x = 14 x = 7/3 = 2.33 x^2 - 5 must be + so |x| >/= sqrt 5 or 2.24
*January 1, 2016*

**Calculus**

hanging mass = 100 + 2 x F = g(100+2x) do dW = F dx from x = 0 to x = 20 W = g (100 x + x^2) at 20 - at 0 = g (2000 + 400) = g (2400) = 23520 Joules then from x = 0 to x = 10 g (1000 + 100) = 1100 g = 10780 Joules subtract I get 12740 Joules
*December 31, 2015*

**Electric field**

(1/2) m v^2 = q V m is electron mass q is electron charge (assume positive)
*December 31, 2015*

**Trig**

CSC (5PI/6) ?? 6pi/6 or pi is 180 degrees, the - x axis so we are pi/6 or 30 degrees above the - y axis the sin of that angle (150 deg) is 1/2 so the answer is 1/(1/2) or 2
*December 31, 2015*

**physics**

Torque = I alpha 5.2 * .8 = 1.4 alpha alpha = 2.97 radians/second^2
*December 31, 2015*

**physics**

The current now has three choices for where to go, but the voltage is the same for all three. itotal = V/R + V/r + V/R itotal = 3 V/R = V/(R/3) which is the voltage divided by the equivalent resistance, R/3
*December 31, 2015*

**Science**

The type of force is therefore electrostatic (Coulomb) force in the simple model of atoms.
*December 31, 2015*

**Science**

I am no chemist but those are all compounds between Hydrogen and halogens which desperately want to grab an electron to fill their outer shells so I would expect Hydrogen bonds where the Hydrogen partially gives up its sole electron.
*December 31, 2015*

**Electric field**

1 electron volt or 1.6*10^-19 Joule
*December 31, 2015*

**physics**

Coulomb's law: F = k q1 q2/r^2 E = force on unit charge E = F/1 = k q /r^2 = 9*10^9 * 8*10^-6 /4 1.8 *10^4 Newtons/Coulomb like charges repel so in direction away from positive charge
*December 31, 2015*

**science and technology**

assuming that the force is in the direction of the motion then: 80 * 24 = 1920 Joules
*December 31, 2015*

**physics**

(1/2) m v^2 = (1/2)(250) * 25 because 5^2 = 25 = 3125 Joules
*December 31, 2015*

**physics kinematics**

x is downstream y is across x velocity = -2 y velocity = 4 tan T = -2/4 T = 26.6 degrees from straight across or 90-26.6 = 63.4 from straight upstream magnitude = sqrt(4+16) = 2 sqrt 5 = 4.5
*December 31, 2015*

**Math**

(m b + n g) /(b+g)
*December 30, 2015*

**Math**

280(n+1) = 288 (n) 280 = 8 n n = 35 288 * 35 = 10080 seconds or 2.8 hours
*December 30, 2015*

**math**

LOL - only use positive root if above ground.
*December 30, 2015*

**math**

which is -r +/- sqrt(r^2+d^2)
*December 30, 2015*

**math**

d^2 = h^2 + 2 r h h^2 + 2 r h - d^2 = 0 quadratic h = [ -2r +/- 2 sqrt(r^2+d^2) ]/2
*December 30, 2015*

**Physics**

change in potential energy due to fall = m g (10+x) storage of potential energy in spring = (1/2) k x^2 so (1/2) k x^2 = m g (10 + x) you have everything, solve quadratic for x then: distance below bridge = 10 + x
*December 30, 2015*

**100 kg bullet?**

I assume a typo and bullet is 10 grams initial momentum of bullet and mass before collision = 500 * 10^-2 kg + 0 * 2 kg = 5 kg m/s the momentum just after collision will be the same with a mass now of 2.010 kg and speed v so 2.010 v = 5 calculate v from that now the pendulum ...
*December 30, 2015*

**math**

i and i+5 3(i+5) = 11 + i^2 3 i + 15 = 11 + i^2 i^2 - 3 i - 4 = 0 (i-4)(i+1) = 0 i = 4 or i = -1 try 4 then i+5 = 9 is 9 five more than 4, yes is 27 = 11 + 16 yes so 4 and 9 work try -1 i+5 = 4 is 12 = 11 + (-1)^2 yes so -1 and 4 work
*December 30, 2015*

**Algebra I**

-6(3x+1) ----------- 2 (3x+1) = -3
*December 30, 2015*

**math**

try 4 (5 + 6 g)
*December 30, 2015*

**Precalculus- HELP!**

hmmm think it means t = 33 + 7 sin [ (pi/12)(x-11) ] when x = 0 we have sin [-11 pi/12] which is - sin [11*180/12] = -sin(165 degrees) = -.259 so t = 33 - 7(.259) = 31.2 degrees F
*December 30, 2015*

**science,physics**

If you found this question in a physics book, watch the wording. If they asked for "distance", then Ms Sue told you how to do it. If they ask for "displacement", that is the magnitude of the vector between the start and the finish which is zero.
*December 30, 2015*

**Math**

1.3 * 6 * 160
*December 30, 2015*

**math**

lost 5 won 15 played 20
*December 30, 2015*

**Math**

k = m +7 3(m+7) + 5 m = 165
*December 30, 2015*

**SOCIAL STUDIES**

I thought it an extremely interesting article but wished it contained more details of garden construction. It was also somewhat disjointed and repetitive.
*December 29, 2015*

**Math**

The center has to be on the line y = x if the circle is tangent to the x and y axes. so center on 3 x = 3 y = 9 or (3,3) and the radius is 3 so (x-3)^2 + (y-3)^2 = 9
*December 29, 2015*

**linear programming**

p = number of printmasters s = number of speedmasters (1) vol = 10 p + 5 s < 2000 (2) wt = 5000 p + 600 s < 300000 maximize gain = g = 125000 p + 30000 s p on x axis , s on y axis do quadrant one vol line (0,400) to (200,0) wt line (0,500) to (60,0) find intersection ...
*December 29, 2015*

**Chemistry**

CuSO4 is 159.6 grams/ mol 5 M would be 159.6*5 = 798 grams/1000 mL so we need 79.8 grams to make 100 mL of 5M take one tenth of that solution, 10 mL and mix it with 90 mL of water to make 100mL of .5 M take one fifth of that .5 M solution which is 20 mL and mix with 80 mL of ...
*December 29, 2015*

**Math**

p + n = 90 but we know that p is 2 n so 2n + n = 90 or 3 n = 90
*December 29, 2015*

**Math**

p + n = 90 p = 2 n 3 n = 90 n = 30 p = 60
*December 29, 2015*

**math**

You are welcome.
*December 29, 2015*

**math**

(3/4) x = 3 1/2 3 x / 4 = 7/2 3 x = 14 x = 14/3 = 4 2/3
*December 29, 2015*

**math**

8 1/2 / 2 5/6 17/2 / 17/6 1/2 / 1/6 3
*December 29, 2015*

**math**

25 in urn 1 25 in urn 2 2 white - 3/25 * 10/25 2 red - 7/25 * 6/25 2 black - 15/25 * 9/25 add the results
*December 29, 2015*

**maths physics chemistry**

conservation of mass conservation of energy
*December 29, 2015*

**basic mathematics**

for the first draw 20 balls in the box for the second there are 19 the rest is obvious. For example both white ball one: 10/20 =1/2 ball two: 9/19 so (1/2)(9/19) = 9/38
*December 29, 2015*

**Algebra 1 Solving Systems Using Elimination**

I got (-2,6)
*December 28, 2015*

**math**

she drove home 390+70 You need to know the 70 the 164 was part of her vacation there.
*December 28, 2015*

**Physics**

fall 3300 m range = 9400 m speed = s u = constant horizontal speed = s cos 35 = .819 s if t is time in air then t = 9400 / .819 s = 11,474/s Vi = initial vertical speed = s sin 35 = .574 s z = altitude z = 3300 + Vi t - 4.9 t^2 ground is z = 0 so if t is the time in the air ...
*December 28, 2015*

**history**

Whoever your teacher is sure chooses some amusing alternative answers to questions !
*December 28, 2015*

**chemistry, physics please help**

That looks right to me although I call it latent heat of fusion.
*December 28, 2015*