Sunday
February 14, 2016

Posts by Damon

Total # Posts: 25,228

Algebra 1
19/2 = 9.5 !!!!
January 4, 2016

Algebra 1
( -2 , -19/2 ) ?
January 4, 2016

Algebra 1
Now you try. I did the last one.
January 4, 2016

Algebra 1
-x+2=3x-1 4x = 3 x = .75 then y = 1.25 so ( .75 , 1.25 )
January 4, 2016

Science -- Check my Answer Plz
you had typed 540*10^4 it should be 5.40 * 10^4
January 4, 2016

Science -- Check my Answer Plz
You will need 540 calories per gram water is 1 mL or 1 cm^3 per gram so I get 540 * 100 csl which is 5.40 * 10^4 cal I hope B is a typo and should be 5.40*10^4
January 4, 2016

Science -- Explaination on Heat Capacity?
You are welcome, good luck.
January 4, 2016

Science -- Explaination on Heat Capacity?
Oh my, you question is not about heat capacity but about the latent heat of fusion of water. to melt one gram of ice at 0 deg C requires 224 Joules or 79.8 Calories so to melt 10 grams requires 2240 Joules or 798 calories (so pick 800) specific heat capacity is when there is a...
January 4, 2016

Math
number of spots for players over the season = 42 * 9 = 378 378/14 = 27 games for each player
January 4, 2016

math
of course now that you mention it, adding a number to itself is kind of like multiplying it by two if it were six instead of five 6+6 = 12 2*6 = 12
January 4, 2016

math
2 n = n + 5 ? n = 5
January 4, 2016

Geometry (again)
You could maybe see if a^2+a^2 = c^2 or in the trapezoid if the two diagonals are equal
January 4, 2016

Algebra
T(t)= 12 + 3 (t-7)
January 4, 2016

Rational Numbers
Well done !
January 4, 2016

Rational Numbers
You are welcome.
January 4, 2016

Rational Numbers
A. Sometimes 22/7 is used for pi HOWEVER it is only an approximation. There are no two whole numbers you can divide and get pi. pi is therefore IRRATIONAL B no way, irrational C no way, irrational D 4/3 YES, finally
January 4, 2016

U.S. History
.... and now ?
January 4, 2016

Math
let u = sin x so du/dx = cos x y = cos^-1 (u) dy/dx = - [1/(1-u^2)^.5 ] du/dx = -[ 1/cos x] cos x = -1 we agree
January 4, 2016

math
540/27 = 20
January 4, 2016

physics
bullet mass + wood mass = 2.107 kg potential energy if up 0.4 meter: I assume this is along the circumference so .4 = theta * 2 = theta = .2 radians = 11.5 degrees distance up from bottom = 2 (1-cos theta) = .0803 meters so energy at top = m g h =2.107*9.81*.0803 = 1.66 Joules...
January 4, 2016

Math Complicated
You are welcome.
January 4, 2016

Math Complicated
Yes, you have it :)
January 4, 2016

Math
(24/48)(x^4/x^2) (y^2/y) (1/2) x^2 y
January 4, 2016

physics
vertical problem: v = Vi - 9.81 t v = 0 at the top t = Vi/9.81 at the top which is 100 meters h = Vi t - 4.9 t^2 100 = Vi^2/9.81 - .5*9.81 (Vi^2/9.81^2) 100 = .5Vi^2/9.81 Vi = 44.3 m/s T = angle up from horizontal sin T = 44.3/50 T = 62.4 degrees t = 2 * Vi/9.81 = 2*44.3/9.81...
January 4, 2016

US History
nope: http://www.dummies.com/how-to/content/what-is-the-presidents-cabinet.html
January 4, 2016

Science
I agree with YRN on all others
January 4, 2016

Science
5 is C
January 4, 2016

Science
Al is 27 g/mol so we have 3 * (13.5/27) * 6 *10^23 electrons lost
January 4, 2016

Science
M = metal we have MCl2 1 mol chlorine and 1/2 mol of metal 35.5 g chlorine in a mol 111 - 35.5 = 75.5 g of M so M is 75.5 * 2 = 151 g/mol maybe Europium
January 4, 2016

Physic
sorry, no it is ok well, for a plane wave d^2y/dx^2 must be (1/v^2)d^2y/dt^2 if y = x^2 + v^2 t^2 dy/dx = 2x d^2y/dx^2 = 2 dy/dt = 2 v^2 t d^2y/dt^2 = 2 v^2 2 = (1/v^2) 2 v^2
January 4, 2016

Physic
well, for a plane wave d^2y/dx^2 must be (1/v^2)d^2y/dt^2 if y = x^2 + v^2 t^2 dy/dx = 2x d^2y/dx^2 = 2 dy/dt = 2 v^2 t d^2y/dt^2 = 2 v^2 so it is not and you should have written x^2 + (1/v^2) t^2
January 4, 2016

Science
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/restmp.html
January 4, 2016

physics
west momentum = 1500 * 90 north momentum = 1400 * 72 final west momentum = 2900 Vwest final north momentum = 2900 Vnorth final = initial speed = sqrt(Vwest^2 + Vnorth^2) tan angle west of north = Vwest/Vnorth
January 4, 2016

Math
upstream speed = u - c downstream speed = u + c d = (u-c)(3.5) = (u+c)(2.1) but c = 3 so (u-3)(3.5)=(u+3)(2.1) 3.5 u - 10.5 = 2.1 u + 6.3 1.4 u = 16.8
January 4, 2016

Another Calculus help plz
I do not know if you mean tan (x/2) or (1/2) tan x Parentheses are important. I will just do y = tan x = sin x / cos x perhaps that will get you going. dy/dx = (cos^2 x + sin^2 x)/cos^2 x = 1/cos^2 x
January 4, 2016

Calculus help plz
cos^2 mx dx ? = mx/2 + sin(2mx) / 2m
January 4, 2016

Math
22.05 = 1960 (r/4) 1960 r = 88.20 r = .045 so 4.5 %
January 4, 2016

Math
3 * .04 * 820
January 3, 2016

Math
.75 * 52
January 3, 2016

Science (Mrs.sue please help)
Yes.
January 3, 2016

Need the picture
Without the picture there is not much hope of help.
January 3, 2016

Algebra
slope of zero means constant y (4,9) and (3,9) and calling the second coordinate x is presumably done to confuse the student.
January 3, 2016

Physic - ah got it !
http://www.thefreedictionary.com/physic
January 3, 2016

Physic
By the way is a physic something you take for a stomach ache?
January 3, 2016

Physic
work = force in the direction of motion * distance normal force down = weight - tension component up = m g - F sin 23 friction force = .33(mg-F sin 23) drag force = F cos 23 no accelration so friction force = drag force F cos 23 = .33 (mg-F sin 23) solve for F we want the ...
January 3, 2016

Science
model ? example Bohr atom ?
January 3, 2016

Calculus
http://mathworld.wolfram.com/Semicircle.html look at integration for weighted mean, then divide by area. pi r^2/2
January 3, 2016

Calculus
4 r/3pi is the semicircle do the outer one, then subtract the inner one. See for example: http://en.wikipedia.org/wiki/List_of_centroids
January 3, 2016

math
(-1)^ even power = 1
January 3, 2016

Math
it is 4, the distance from west 2 to east 2 :)
January 3, 2016

Math
n^2 - 4 = 21 + 9 n n^2 - 9 n -21 = 0 (n-7)(n+3) = 0 n = 7 so the smallest is 5
January 3, 2016

Math
They are POSITIVE, odd numbers are OUT so they differ by TWO n-2 , n , n+2 (n-2)(n+2) = 21 + 9 n
January 3, 2016

math
x^4 - 5 x^3 + 5 x^2 + 4 x - 61 = 0 find the roots try http://www.wolframalpha.com/input/?i=x^4+-+5+x^3+%2B+5+x^2+%2B+4+x+-+61+%3D+0+&x=5&y=5
January 3, 2016

Algebra
55 t +120 - 40 t = 135 15 t = 15 t = 1 hour at 55 so 55 miles on highway 2 hours at 40 = 80 miles on dirt
January 3, 2016

Algebra
55 t + 40 (3-t) = 135
January 3, 2016

math
I will leave you to get s now
January 3, 2016

math
.866 s = 950 sin h - 90 .866 s = 1645 cos h ---------------------subtract 950 sin h = 1645 cos h + 90 or 950 sin h - 1645 cos h = 90 for various values of h h , left side 60 , .224 61 , 33.4 62 , 66.5 63 , 99.6 so steer 62.5 degrees west of south 65 , 165 70 , 331
January 3, 2016

math
He must stay on a course of S 60 W. We must find the heading :) h is degrees heading west of south say his speed over the ground is s then west speed over ground = s sin 60 = 950 sin h - 90 and south speed over ground = s cos 60 = 950 cos h so .866 s = 950 sin h - 90 .5 s = ...
January 3, 2016

Does not make sense
You say Ruth has 130 then ask how much she has.
January 3, 2016

Geography (Ms.Sue ) Help
Interesting - stress seems to lead to more babies. War torn Afganistan is top at 2.4 followed by Maldives threatened by flooding at 1.9 Quiet but lonely Nepal at 1.2 Quiet Sri Lanka (since the tsunami) lowest at 0.8
January 3, 2016

Geography (Ms.Sue ) Help
http://www.google.com/search?q=population+growth+nepal&ie=utf-8&oe=utf-8 http://www.google.com/search?q=population+growth+afganistan&ie=utf-8&oe=utf-8 http://www.google.com/search?q=population+growth+sri+lanka&ie=utf-8&oe=utf-8 http://www.google.com/search?q=population+growth+...
January 3, 2016

math
6-4 5-3 4-2 3-1 4-6 3-5 2-4 1-3 so 8 work out of how many 6 * 6 I think or 36 so I get 8/36 = 2/9 see: http://www.freemathhelp.com/rolling-dice.html
January 3, 2016

physics
Ah, did not think of that :)
January 3, 2016

physics - No way - directions not defined
Is it pushed up or down the slope? Is that 20 m/s up slope or down slope? I will assume both are UP and you will have to get it straight yourself. weight component down slope = m g sin 37 = 80 * 9.81 * sin 37 = 472 N If you are pushing up with 400 N, you lose, at least on ...
January 3, 2016

chemistry
Maybe lea nitrate ?
January 3, 2016

math
a7 = a + d(6) = 21 {so 2a+12 d = 42} sum of first 13 = (13/2)(2a + 12d) = (13/2)(42) = 13 * 21 = 273 look at: http://www.mathsisfun.com/algebra/sequences-sums-arithmetic.html
January 3, 2016

Calculus pz help urgently
-.25 cos (2x-pi/4) - .25 x sqrt 2 + c
January 3, 2016

Calculus pz help urgently
note we no longer have sine curves with zero mean value but now have an average plus a cosine curve with twice the frequency.
January 3, 2016

Calculus pz help urgently
note sin pi/4 = sqrt2/2 -.25 cos (2x-pi/4) - .25 sqrt 2
January 3, 2016

no, wrong
I guess maybe you mean sin x cos(x-pi/4)dx sin x cos y = .5 sin (x+y) + .5 sin (x-y) (remember "beat frequency" ) so .5sin ( 2x-pi/4)dx + .5sin (pi/4)dx
January 3, 2016

Calculus pz help urgently
I guess maybe you mean sin x cos(x-pi/4)dx sin x cos y = .5( sin x +sin y) + .5 (sin x - sin y) (remember "beat frequency" ) so .5(sin x + sin(x-pi/4)dx + .5(sin x - sin(x-pi/4)dx ---------------------------- add (oh my) sin x dx -cos x + c
January 3, 2016

sorry, do not know
As far as I know zero to the anything is zero.
January 3, 2016

Math
You are welcome.
January 3, 2016

Math
a) 2/7 b) 5/7 * 9/24 c) assume 6 am for maximum inconvenience so 8/24
January 3, 2016

math
20/16 divide top and bottom by 4 5/4
January 3, 2016

math
still 5/4
January 3, 2016

Math
c T = wavelength - 3 m (1/4)3 = .75 meters = 750 cm
January 3, 2016

Math
how long would a (1/4) wave antenna be? (use c = 3*10^8 meters/second)
January 3, 2016

math- HELP!
$2600 initial at 8% compounded continuously
January 2, 2016

Do you get it now?
Get the idea? Richer # = log of amplitude. so you take 27 times the antilog and then take the log of that
January 2, 2016

Math Exponetial Function Problem Question?
here slowly Richer number = 3.2 3.2 is log of amplitude A log A = 3.2 10^logA = A = 10^3.2 = 10^3 * 10^.2 so A = 10^3 * 1.5848 Now Multiply THAT by your 27 B = 10^4 * 4.27921 log B = log 4 + log 4.27921 = 4.631 which is your new Richter #
January 2, 2016

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

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