# Posts by Steve

Total # Posts: 52,287

calculus
well, you have tanz = r^2 tan2? z = arctan(r^2 tan2?) ?z/?r = (2r tan2?)/((r^2 tan2?)^2+1) ?z/?? = (2r^2 sec^2(2?))/((r^2 tan2?)^2+1) the second partials get a bit messy, but you can get them here: http://www.wolframalpha.com/input/?i=d%5E2%2Fdr%5E2+arctan(r%5E2+tan2%CE%B8) ...

calculus
just crank it out ?u/?x = 2x/(x^2+y^2) ?u/?y = 2y/(x^2+y^2 ?v/?x = -2y/(x^2+y^2) ?v/?y = 2x/(x^2+y^2

MATH
the link is missing a domain name, such as http://pictures.com/...

math
16 2/3% = 1/6 1/6 * 9 = ...

math
12* 5/3 = 5 * 12/3 = ...

maths

maths

maths
this is the same as cos30/sin30 + sin30*cot30 = cot30(1+sin30) = ?3 (1+1/2) = 3?3/2

maths
These are standard angles, whose functions you would do well to learn Cos45+sin60-tan30 = 1/?2 + ?3/2 - 1/?3 = (3?2 + ?3)/6

maths
well, (1+cot²x) = csc²x

Geometry
there are many possible line segments drawn from a to bc

Maths
301 They all leave remainder

Algebra
what's the trouble? They say S = ?(30fL) just plug in your numbers and solve for L

Algebra
If the painting has length x and height y, and the frame has width w, then we have x+2w = 10 y+2w = 8 x^2+y^2 = 100 Now just solve for w

Math
I get 104. What do you get?

Math
try using <= for "less than or equal" "under 12" means "less than 12" so, what do you think?

Math
n > 130-87

Math Check! #3
yeah, but how does that relate to choosing 4 players from a group of 8?

Math Check! #3
Hmmm. How did you get 336? This is just a "choose 4 of 8" combination. 336 = P(8,3) How does that relate to this problem. I suspect you just guessed.

maths
not sure what -< and +< mean

Math
2/(3/4) = x/30

Algebra2
Thank you

Algebra2
The water level varies from 12 inches at low tide to 52 inches at high tide. Low tide occurs at 9:15 am. High tide occurs at 3:30 pm. What is a cosine function that models the variation in inches above and below the water level as a function of time and hours since 9:15 am? ...

Geometry
correct

Algebra2
The function f(theta) and g (theta) are sine functions where f(0)=g(0)=0. The amplitude of f (theta) is twice the amplitude of g(theta). The period of f(theta) is one-half the period of g(theta). If g (theta) has a period of 2pi and fpi/4=4. Write the function rule for g(theta...

MATH
since you give no indications of any side lengths, it's kinda hard for us to say, right? and besides, area is in cm^2, dontcha know

Algebra2
thank you

Algebra2
for which value of theta is tan theta equal to sin theta? My answer is pi

math
42.75*1.18

Math
if you mean the angle is 20°, then the radius r of the circle can be found using' 5/r = sin10° Now you know r, so you can find the area of the circle...

chemistry
how many moles in 5.3g? Molarity is moles/liter

Math
since xy=48 for each pair, B is correct.

Algebra2
Thank you

Algebra2
cos?+1 = 0 cot(?/2) = 0

Algebra2
Write three trigonometric equations each with the complete solution pi+2pin

Physics-Circuits

Math
180 degrees surely your geometry text proved that most basic fact of triangles!

Math
depends on your clock. Some keep 24-hour time. and who says "army" time isn't real? It's just not "civilian" time feet are just as real as meters -- it just depends on your yardstick ...

HELP
probably for the same reason you wasted our time posting the same stupid question again ...

science
ummm ... because they grow on cherry trees? Or maybe because cherries happen where those blossoms are. Or maybe because they've never been pollinated ...

physics
a) how long does it take to fall 132m? If it takes t seconds, b) the kit lands 68.9t meters away from where it was dropped. No idea how far away from the survivor that happened.

Chemistry
hint: nuclear reaction.

Math Percents
P is 150% more than S.

math
If h is the height of the building above S, then we have h cot30° = (h-10)cot60°

Ratios
If the lightest is x, then the heaviest is 3x. So, 3x = x+8 x = 4 So, the parts are 4,8,12 oz

math
x^2+6 is the result, if you started with x.

Math
it's still a direct relationship. It just happens that the constant of proportionality is negative. The "amount you lose" increases with the running time.

math
I'll get you started... (2n^2-7n+2)*(3n+1) = (2n^2-7n+2)*3n + (2n^2-7n+2)*1 Now just expand each factor term by term, simplifying at the end.

Math
1:25 = 20:500

Science
avg speed = total_distance/total_time so, just plug in your numbers

math
don' see no steenkeng tables, but something like -1 -4 0 -3 1 -2 2 -1 3 0 ...

math
c(1+r)(1-0.15) = c what r should be depends on how much profit he expects to make. a 17.6% markup will just break even. a 20% markup will provide a 2% profit.

Science
since s = vt = 1/2 at^2, you need 6t = 1/2 * 4 t^2 3t = t^2 t = 3

science
?(100^2+70^2)

math
Your typing skills can use some improvement as well. I'd say your past laziness is now catching up to you. Too bad. Seek some in-person help. Trying to do it piecemeal here will not cut it.

Statistic
so, assume 100 candies, with 15 yellow. Your probability will be approximately 15/100 * 85/99 * 84/98 = 0.11 = 11%

Math
c'mon, guy, just write the words as algebra. If the pool has width w, then its length is w+6. Now work with the total area: (w+8)(w+6+8) = w(w+6) + 576 Now solve for w and then w+6.

Math
If the ladder has length z, then (.3z)^2+20^2 = z^2 z ? 21 ft

Math
just plug in your numbers and solve for h 900 = ?(h^2+8000h) h^2+8000h-900^2 = 0 h = 100

Math
If the base is b, then (1/2)bh = 30 (1/2)b(2b-2) = 30 ...

Geometry
Draw a side view of the figure. Using similar triangles, it is clear that (9-h)/r = 9/6 h = 9 - 3r/2 Now we can compare volumes, and we find 1/3 pi * 6^2 * 9 = 9 pi r^2 h 108 = 9r^2(9 - 3r/2) r^3 - 6r^2 + 8 = 0 r = 1.3054

Science
google the topic, and you will get lots of information.

Science
correct

Geometry
two ends with total area 2pi r^2 curved side with area 2pi r h area = 2pi*r(r+h) = 748pi

math
#3 ok #4 - better check again how many marbles out of 30 are green or purple.

recall the formula for the area of a trapezoid: A = (B+b)h/2 Its area is the average of the areas of the rectangles formed using the lengths of its bases: the left and right function values!

scienice
amplitude and wavelength

Pre cal
see your previous post. The horizontal speed is constant.

Geometry
the ratio of the volumes is the similarity ratio cubed. so, you want ?(135:625) = ?(5*27:5*125) = 3:5

Pre cal
then use that t and multiply by the constant horizontal speed of 110 cos45°

Pre cal
just solve for t in h(t) = 2 + (110 sin45°)t - 16t^2 = 0

math
a+b+c = 770 a = 2/9 (b+c) ==> b+c = 9a/2 a + 9a/2 = 770 ...

Physics special relativity
1ly = 9.454254*10^15 m 1y = 3.1536*10^7 s c = 2.99792*10^8 m/s 23000ly/30y = (2.3*10^4 * 9.454254*10^15)/(30*3.1536*10^7) = 2.298409*10^11 m/s see what the Lorentz factor is for 0.99999915c and I'm sure it will work out.

maths
(K+L)/(K-L) divide top and bottom by L: (K/L+1)/(K/L-1) = (7+1)/(7-1) = 4/3

maths
convert all to decimals, or use a common denominator of 60. Then comparisons are easy.

math
4 vowels, 5 consonants D,C from first half of alphabet How can D or C occupy only the first position? One of them has to be somewhere else in the permutation.

Precalculus
z^4+z^2+1 = 0 (z^2-z+1)(z^2+z+1) = 0 one root is z = (1+?3 i)/2 = cis(pi/3) so, z^3 = -1 That means z^6 = 1

math
oops. Forgot to edit my id...

Algebra
amplitude: (14-4)/2 = 5 center line: (14+4)/2 = 9 so, we can start with y = 9cos(kx) the period is 5+5 = 10 hours, so 2?/k = 10, making k=?/5 y = 9cos(?/5 x) The high tide was at 7:00, rather than midnight, so y = 9cos(?/5 (x-7)) or y = 9cos(?/5 x - 7?/5) see http://www....

Geometry
Interesting. I did it like this: 2x+2y = 50, so x+y=25 x+y+h = 40 25+h = 40 h = 15

Geometry
works for me. I hope you calculated BD and didn't just guess around till you got a number that worked.

math
.09x + .05(20000-x) = 1680

Geometry
the distance is ?(12^2+(15-10)^2) = 13 Maybe you should have shown your work.

geometry
drop an altitude from M to P on KN. Then PM = ?(15^2-9^2) = 12 the area is thus (9+18)/2 * 12

Science
what do you think?

math
4.250 anything less, say, 4.249 will round down to 2.2

math
4.30 I think

Math
each side of the triangle is the sum of two radii.

trig
h = 2+10sin58°

math
x y -2 9 -1 4 0 -1 1 -6 2 -11 Note that as x goes up by 1, y goes down by 5. So, start with y = -5x Now, y(0) = -1, so the rule is y = -5x-1

Algebra 2
take a look at the graphs, and it should be clear. Or, study your text and apply the rules. http://www.wolframalpha.com/input/?i=plot+y%3D1%2Fx,+y%3D1%2F(2x-4)

Algebra
(2?5+3?7)^2 (2?5)^2 + 2(2?5)(3?7) + (3?7)^2 4*5 + 2*2*3*?35 + 9*7 ...

chemistry
the theoretical yield is 2 moles of CO2 for each mole of C2H6 So, how many moles of C2H6 did you use? how many moles of CO2 in 5.76g? compare your yield with the possible yield.

Algebra/Trig
the height the ladder will reach is 12sin75°

Trig
h = 2+10sin58°

Math
the horizontal speed is constant, at 90cos60° ft/s, so just use that speed for 3 seconds to find the distance.

math
just like the previous ball team question. You're not going to put in any effort?

math
this is just like the last one. Just write an equation for each statement. To start with, r+w+b = 28 ...

math
If they lost x, then x + 3x+14 = 130

Maths
the volumes are A:?r^2(8h) = 8?r^2h B:?(4r)^2h = 16?r^2h