catsovermen

I have been trying to sugar wax and am not succeeding. I have tried several different recipes for the wax, and the first time didn't fail miserably but didn't remove all the hair. Ever since then I've tried several different things that I saw on YouTube, read online, etc., but I cannot get the wax to stick to the hair. Is it overdone? Underdone? Please send tips.

A friend and I are planning to travel to Colombia and are trying to decide if we should visit Barranquilla for a few days. We plan on spending time in Bogota and Medellin as well. There is a wealth of information for those two cities, but I am having trouble finding anything recent regarding Barranquilla. If you have been, any comments/advice you can give would be appreciated.

The star HIP72509 has an apparent magnitude of +12.1 and a parallax angle of 0.222".

a) Determine its absolute magnitude. Using M = m-5log(d)+5, I have determined that M = +13.8, which agrees with the answer in the back of the book.

b) Fine the approximte ratio of the luminosity of HIP72509 to the Sun's luminosity. L = 4pid^2b. I know the values for 4, pi, and d, but I don't know b. I can't have two unkowns in an equation. Well, I can, but who wants to go through that nightmare of solving, when I know I'm just missing something? I can't find any information for calculating brightness other than b = L/4pid^2, which is the same as above.

Last year my husband and I spread some K-Grow grass seed in our culvert to attempt to get grass to grow there, expanded the sprinkler system, et. al. This resulted in the most heinous substance growing where the grass seed was spread. I have NO idea what it is. It is gelatinous, green, slimy, if you walk in it your shoes are clogged with the stuff, but it grows on the surface because if you drag a rake across it it comes up - not entirely because there is so much. I live in Beaufort, SC, so am in climate zone 8. Does anyone know of good sites where I can identify this stuff and learn how to get rid of it? From the sites I have visited it doesn't fit the description of fungi, molds, mushrooms, or any of the usual suspects.

I am studying for an astronomy test, and a sample question is about planetary mass. Would you let me know if I am solving this correctly?

The planet discovered orbiting the star 70 Virginis, 59 light years from Earth, moves in an orbit with semimajor axis of .48AU and eccentricity of 0.40. The period of the orbit is 116.7 days. Find the mass of 70 Virginis. (Hint: Ignore the mass of the planet when making your calculations.

I would apply Newton's version of Kepler's Third Law to solve. The first step is to convert the period from 116.7 days to 1.00829 * 10^7 seconds, and the semimajor axis from 0.48AU to 7.1808 * 10^10m. Filling in:

mass = [4pi^2 (7.1808 * 10^10)^3] / [(6.67 * 10^-11)(1.00829 * 10^7)^3]

mass = 2.15567 * 10^30 kg

During the period of the most intense bombardment by space debris, a new 1-km-raduis crater formed somewhere on the Moon about once per century. During the same period, what was the probability that such a crater would be created within 1km of a certain location on the Moon during a 100-year period? During a 10^6-year period?

For the first question, there is a one in surface area of the moon chance, or 1/3.973 * 10^7 chance, or 2.6 * 10^-8. Book answer is 8.4 * 10^-8. What am I missing here? Even if I take that it can only hit one face of the moon, I sill only gget 5.27 * 10^-8.

I should be able to extrapolate the second part once I get the correct result for the first part.

THANK YOU!!

A hydrogen atom has a mass of 1.673*10^-27kg, and the temperature of the Sun's surface is 5800K. What is the average speed of hydrogem atoms at the Sun's surface?

I am using the formula for average speed v=sqrt[(3kT)/m]

For k I am using 1.38 * 10^-23J/K

When I plug these in to the formula, I get

sqrt{ [3 (1.38 * 10^-23) (5800)] / (1.673*10^-27)}

And when I get the powerful brain of my TI-89 behind it, the result is 11980.3 m/s, or 11.9803 km/s. However, my book gives the answer of 1.2 km/s. Using rounding with my results, I am off by a factor of 10. After working on several of these, I am brain numb to locating my error. Can you help me out?

THANK YOU!

Calculate the wavelength of P-delta, the fourth wavelength in te Paschen series.

I think I now understand that P-delta is the wavelength for photons between the n=3 and n=7 orbits. If I use those numbers for the Ryberg formula, I get:

1/wavelength = (1.097 * 10^7 m^-1) * [(1/7^2) - (1/3^2)]

Am I even on the right track? I'm coming up with CRAZY numbers.

I asked a question earlier about missing variables, and the answer was one of the variables in negligible. Taking that sage and wonderful advice, I then went to solve for the second variable, and this is what I came up with:

Formula: P^2 = [4pi^2 / G(m1 + m2)]a^3

Subbing the known, and not worrying about the mass of the satellite (the negligible variable), I come up with:

86400^2 (sidereal period in seconds) = [4pi^2 / (6.67 * 10^-11)(5.98 * 10^24)]a^3

7464960000 = [4pi^2 / 3.98866 * 10^14]a^3

This gets you 4.22505 * 10^7 m or 42250.5 km. This is close, but doesn't match the 43,200km the book claims the answer to be. Did I go wrong, or is this a rounding issue of astronomical proportions?

A satellite is said to be in a "geosynchronous" orbit. At what distance from the center of the Earth must such a satellite be place into orbit?

So, I know if I apply Newton's form of Kepler's third law, I can get the semimajor axis. However, I'm a bit stuck on how to find this when I don't know the mass of the satellite. I can find the Earth's mass, I know the constant, and I know the sidereal period of a satellite in geosynchronous orbit is 24 hours, or 86400 seconds.

Any suggestions on what I'm missing? Thank you!!

I am in the market for a car, and am looking at a 2009 Impala. They are currently offering a $2,500 buyer incentive, but I want to know how the trend for incentives has gone in the past. If they are going to make that $4,000 on October 1, it's worth the wait, or perhaps is something I can use for bargaining position. Does anyone know where to find this information? I have tried Edmunds, et. al., but may be looking in the wrong place.

Durin an occultation of Jupiter by the Moonn, an astronomer notices that it takes the Moon's edge 90 seconds to cover Jupiter's disk completely. If the Moon's motion is assumed to be uniform and the occultation was "central", find the angular diameter of Jupiter. (Assume that Jupiter does not appear to move against the background of stars during this brief 90-second interval. You will need to convert the Moon's angular spped from degrees per day to arcseconds per second.)

The first part: moon's angular speed is 360 degrees in 27.32 days (using the sidereal year), which is 13.1772 degrees / day. With 60 arcminutes in a degree, and 60 arcseconds in an arcminute, that is 3600 arcseconds per degree. In arcseconds, the moon's angular speed is 47437.92 arcseconds / day. With 86400 seconds in a day, that's 47437.92 arcseconds / 86400 seconds, or 0.54905 arcseconds / second. Am I right so far?

A nursing school entrance exam is normally distributed with mean for success of 64% and standard deviation of 5%. A sample of 50 students from Borton Univ. took the test and their scores recorded. Find the probability that:

a) More than 60% passed the test.

b) At most 40% passed the test.

I have used the Central Limit Theorem and Normal Approximations to Binomial Distributions, and I get extremely high z-values using both methods. Since 60% is within one standard deviation of the mean, the probability should not be a 1. If you could show me what to do so I can figure out where I'm going wrong, I'd appreciate it.

For (b), the 40% is almost 5 standard deviations from mean, so the probability is infinitesimally small, approximately zero. Is this correct?

Thank you!

A nursing school entrace exam is normally distributed with mean for success of 64% and standard deviation of 5%. A sample of 50 students from Borton University took the test and their scores recorded. Find the probability that:

a) More than 60% passed the test,

and

b) At most 40% passed the test.

My work:

a) P(x>60%), which converts to P(z>-5.65691), which is extremely close to 1.

b) P(x<=40%), which converts to P(z<=-33.9415), which is also extremely close to 1.

To convert to z-scores, using the Central Limit Theorem, I use the formula (x - mean) / standard error. Standard error is standard deviation / sqrt(n).

All this seems pretty straight forward, but I'm missing a step or going wrong somewhere, because while (b) 40% is 4.8 standard deviations from mean, so that probability should be very close to zero, and (a) .60 is within one standard deviation of mean so should be closer to the 68% as defined in the Empirical Rule.

Help me, please. Where am I going wrong?

I USED to think I was smart, and I USED to think I was good at math, and then I met calculus. I need some help on volumes and arc lengths, please.

a) Find the volume of the solid generated by revolving the region bounded by the graphs of the equations about the y-axis

y=sqrt(2x), y=0, x=2; for this one, using the disk method, I have gotten 19pi/5, 79pi/5, and 38pi/5. Using the shell method, I get 32pi/5. Are any of them right?

-x^2+8x-12, y=0; Using the disk method I get 19pi/5. Using the shell method I get 2pi/7. Are either of these right?

Find the volume of the solid generated by revolving the region bounded by the graphs of the equations about the x-axis:

y=srt[x-2], y=0, x=6; Using this disk method I get 8pi. Is it correct?

y=x^3, y=1, x=2; Using the disk method I get 8pi/7. Is it correct?

Find the volume of the solid generated by revolving the region bounded by the graphs of the equations about the line x=4:

y=x+3, x=0, y=0, x=3; Using the shell method I get 63pi. Is it correct?

y = -5/(x-5), x=0, y=0, x=4; Using a combination of the shell method and my calculator I get approx. 40.472pi. ???

Find the arc length of the graph of the function over the indicated interval:

y=cosx [0,pi/2] {1.9101} and y = e^(x/2) {this one is REALLY ugly}

For both of these I had to rely on my calculator for the answers, but I would like to know how to solve them. My book doesn't give ANY guidance on the e^(x/2).

I know this is a lot, but I appreciate whatever guidance you can give. THANK YOU!!!

I just want to verify if my two answers are correct:

1) Find the volume of the solid generated by revolving the region bounded by the graphs of the equations bout the y-axis:

e^x; y=0; x=0; x=4

My result is 2pi(e^4+1)

2) Find the volume of the solid generated by revolving the region bounded by the graphs of the equations about the line x=6:

y=x^2+3; x=0; y=0; x=4

My result is 96pi using the shell method, and 176pi using the washer method. Which one is correct?

Thank you!

Find the volume of the solid generated by revolving the region bounded by the graphs of the equations about the x-axis:

y = x+4; y=2; y=5; x=1

I know that volume is pi times the integral of b over a [R(x)]^2 - [r(x)]^2 dx. When I solve this, however, I come up with a -3pi. Volume, naturally, can't be negative, so I think that I must have my R mixed with my r, or I'm using the wrong coordinates for a and b. Could you let me know what R(x), r(x), b and a are so I can check against my work?

THANK YOU!!

I am stuck on four problems.

1) Find the derivative of y = x/(3^x). I get 1/x - x(ln3)/(3^x). My calculator gets 1 - x(ln3)/(3^x). The difference would be whether you take ln of x. In order to equate, don't you have to take the ln of the entire function? Which is right?

2) Find the derivative of y = (x^e)tan(3x). The calculator gives me a really crazy answer, which I'm sure I can simplify, but the give the x^e turning into x^(e-1). If you use the power rule, why isn't it ex^(e-1)?

3) Derivative of y = x^2arccsc(2x). I get 2xarccsc(2x) - 2x^2/l2xlsqrt(4x^2-1). I used the product rule, and the derivatives of inverse trigonometric functions. My calculator returns 2xarccsc(2x) - 2x^2arccsc(2x^2)/sqrt(1-4x^2). Which is correct, and if the calculator what did I do wrong?

4) Find the integral of 8x^-1/sqrt(4x^2-9). I'm a bit confused by what to do here? My calculator brings back [8arctan(sqrt(4x^2-9)/3)]/3. I can see from the answer that this is du/a^2 + u^2 = 1/a arctan u/a + c, where u = sqrt(4x^2-9) and a = 3, BUT how do you work it out that the 8 is still there? And I'm confused about the 8x^-1, because u' would be 8x^+1.

Thank you so much for any assistance you can give.