how do i find the bifurcation for this: d^x/dt^2 = -.3 x - (x - 1)/((x - 1)^2 + a^2)^(3/2) - (x + 1)/((x + 1)^2 + a^2)^(3/2) we've tried using mathematica but it just runs forever...
March 25, 2009
Let P(t) represent the population of a non-native species introduced to a new area for the purposes of harvesting. Suppose we intially introduce P0 = 100 indicidcuals and suppose the population grows exponentially with growth-rate coefficient k=2 if there is no harvesting (for...
February 22, 2009
Suppose a species of fish in a particular lake has a population that is modeled by the logistic population model with growth rate k, carrying capacity N, and time t measured in years. Suppose the growth-rate parameter k=.3 and the carrying capacity N=2500. Suppose P(0)=2500. (...
February 4, 2009
a very light rigid rod with a length of .500m extends straight out from one end of a meterstick. the meterstick is suspended from a pivot at the far end of the rod and is set into oscillation. determine the period of oscillation (hint: use the parallel-axis theorem) i can'...
December 4, 2008
A car moves with speed v on a horizontal circular track of radius R. The height of the car's center of mass is h, and the separation between the inner and outer wheels is d. The road is dry, and the car does not skid. Find the maximum speed the car can have without ...
November 20, 2008
Consider an infinite population with 25% of the elements having the value 1, 25% the value 2, 25% the value 3, and 25% the value 4. If X is the value of a randomly selected item, then X is a discrete random variable whose possible values are 1, 2, 3, and 4. (a) Find the ...
November 5, 2008
A bicycle has wheels 67.3 cm in diameter and pedal cranks 17.5 cm long. The cyclist pedals at a steady cadence of 76.0 rev/min. The chain engages with a front sprocket 15.2 cm in diameter and a rear sprocket 7.00 cm in diameter. Calculate: a) the speed of a link of the chain ...
November 4, 2008
The solubility product of Mg(OH)2 is 1.2 x 10^-11. What minimum OH- concentration must be attained (for example, by adding NaOH) to decrease the Mg concentration in a solution of Mg(NO3)2 to less than 1.0 x 10^-10 M (molar)?
November 1, 2008
The solubility of KNO3 is 155 g per 100 g of water at 75 degrees celcius and 38.0 g at 25 degrees celcius. What mass (in grams) of KNO3 will crystallize out of solution if exactly 100 g of its saturated solution at 75 degrees celcius is cooled to 25 degrees celcius. i found ...
October 15, 2008
A hemoglobin molecule (molar mass =65000 g) can bind up to 4 oxygen molecules. In a certain experiment a .085-L solutoin containing 6.0 g of deoxyhemoglobin was reacted with excess of oxygen in a constant-pressure calorimeter of negligible heat capacity. calculate the enthalpy...
October 4, 2008
The fuel value of hamburger is 3.6kcal/g. If a man eats 1 pound of hamburger for lunch and if none of the energy is stored in his body, estimate the amount of water that would have to be lost in perspiration to keep his body temperature constant. (the heat of vaporization of ...
October 4, 2008
After a .800-nm x-ray photon scatters from a free electron, the electron recoils with a speed equal to 1.20 x 10^6 m/s. (a) What was the Compton Shift in the photon's wavelength? (b) Through what angle was the photon scattered? I got an answer for (a), but when i use it to...
May 7, 2008
A construction worker uses a steep tape to measure the length of an aluminum support column. If the measured length is 18.700 m when the temperature is 21.2 degrees celcius, what is the measured length when the temperature rises to 29.4 degrees celcius. I found the increased ...
March 13, 2008
that one's arcsin. factor it into: 4*integral(1/sqrt(16-(t^2+2t+1)))dt so, 4*integral(1/sqrt(4^2+(t+1)^2))dt divide everything in the sqrt by 4^2 and bring it out as 1/4, 4/4*integral(1/sqrt(1+((t+1)/4)^s))dt) now it's in arcsin form (remember u and du) so your answer ...
February 13, 2008
for a free throw in basketball,find an equation for the final angle to go into the hoop in terms of y and x to the hoop and the initial angle. I can't seem to get an equation with only those variables. I always get stuck with others like time and velocity. how do i do this?
February 3, 2008
Find the velocity of a satellite orbiting above the equator of the earth in geosynchronous orbit (Period=24 hours) in km/hr. The earth's mass M=5.974x10^(24)kg and radius R=6,731 km. G=6.673x10^(-11) m^3/(kg*s^2) Use v=(G*M/R)^(1/2) I plugged everything in and changed the ...
January 17, 2008
Help! I have no idea how to do this. The earth's orbit is nearly circular with a radius R=93x10^6 miles (the eccentricity is e=.017). Find the rate at which the earth's radial vector sweeps out area in units of ft^2/s. What is the magnitude of the vector J=rxr` for the...
January 17, 2008
works cited page
I am doing a works cited page in MLA format. If I have two articles that are from the same website, just different places, do I document it as one source or two different ones?
December 2, 2007
I am not sure about the ordering of the words. Are the following correct? Do you speak French? Vous parlez francaise? I speak a little French. Je parle francais comme ci comme ca. My mom speaks french too. Ma mere parle francais aussi.
September 24, 2007
French for Mischa
Personally, I really like the sound of the language. And I always wanted to go to France, maybe travel or even for work. I am just really interested in French culture. I would love to know some of your 75 good reasons to learn french.
September 22, 2007
I figured I rather do the accents by hand. lol Yeah, I am pretty sure where the accent goes. I was just wondering, how many languages do you know? You seem to know quite a lot.
September 22, 2007
Based on all the questions I've asked. I believe there are no mistakes in these sentences? -J'aime la musique japonaise. -J'ai un frere, il a vingt sept ans. -Elle a vingt ans. -Elle est jeune, elle est jolie. (Should I use jolie or belle?) -Elle aime la danse, le ...
September 22, 2007
Thanks, actually i just start learning french two weeks ago. I have a question from before, you said that the adjective modifies the noun in number (singular/plural) and gender (masculine/feminine) and has nothing to do with the subject. -la musique goes with française ...
September 20, 2007
I know that for a male to say that he is french, we use francais, and for a female, we use francaise. But when a female says that she speaks french, do we use francaise as in Je parle francaise? And when a female says that she likes French music, do we use francaise as in J...
September 18, 2007
Suppose that there is a model with two constraints 1) 120x1+160x2 <=(less than or equal to)450 2) 3x1+10x2 <= 25 and there is a third constraint called min. requirement, orginally this constraint is: 37x1+65x2 >= (greater than or equal to)120 I have to find all values...
September 16, 2007
Suppose there's a model with 2 constraints originally. Now that another constraint is added. Which of the following are possible: 1) feasible region shrinks 2) feasible region stays the same 3) feasible region expands and Which of the following are possible: 1) optimal ...
September 15, 2007
Can anyone help me interpret this poem/prayer? What does it reveal about Mesopotamian religious beliefs and practices? Thanks!! May the wrath of the heart of my god be pacified! May the god who is unknown to me be pacified! May the goddess who is unknown to me be pacified! May...
September 4, 2007
I'm suppose to figure out what the leg is a metaphor for in the following story. I can't figure it out. Any suggestions?! Letter from Gaza by Ghassan Kanafani Dear Mustafa, I have now received your letter, in which you tell me that you've done everything necessary ...
May 22, 2007
given x=2cos(t)+t*sin(t) and y=2sin(t)-t*cost(t), with t:[pi, 2pi] find all critical values. by finding dy/dx and setting it equal to zero, i only find one value, t=6.121, within that domain. that gives you x=.987. I'm suppose to get three other answers. How do i do this?!
May 20, 2007
let y=2x-8. What is the minimum value of the product xy? I'm not really sure how to do this... I tried taking x*(2x-8), and the min is 0. but then i wanted to see if it was the same when solving for x, and i got a min of -8. How do i do this problem? thanks, but i found ...
May 1, 2007
I need to find the centripetal acceleration of my clothes dryer. How would I go about doing it... Would the tangential speed just be 2pi*R*number of rotations/time, or how would I find that? Put a shoe in the dryer. Count the number of times the shoe tumbles in a minute (that ...
May 1, 2007
A force of 250 N is required to stretch a spring 5m from rest. Using Hooke's law, F=kx, how much work, in joules, is required to stretch the spring 7m from rest? The energy required scales with x^2. Multiply 250 J by (7/5)^2.
April 23, 2007
An electron and a proton are each placed at rest in an external uniform electric field of magnitude 520 N/C. Calculate the speed of each particle after 48 ns. None of the equations I have seem to help me. What can I use to solve this problem? I figured it out, but thanks anyway.
April 12, 2007
Three point charges, q1, q2, and q3, lie along the x-axis at x=0, x=3 cm, and x=5 cm, respectively. Calculate the magnitude and direction of the electric force on each of the three points when q1=+6.0 muC, q2=+1.5 muC, and q3=-2.0 muC. I would add the forces. Watch direction. ...
April 11, 2007
What is the area of the region in the first quadrant enclosed by the graph of y=e^(x^2/4) and the line y=0.5? When I graphed the two functions they don't even connect so the answer would be infinity. What am I doing wrong> Integrate y=e^(x^2/4) from x=0 to the point ...
March 27, 2007
Does 1/ln(x+1) converge or diverge? I've tried the nth term test, limit comparison test, and integral test. All I get is inconclusive. The other tests I have (geometric series, p-series, telescoping series, alternating series, and root tests) don't apply. What can I ...
March 22, 2007
A bird perched on a swing the sits 8 cm below a bar has a mass of 52 g, and the base of the swing has a mass of 153 g. The swing and bird are originally at rest, and then the bird takes of horizontally at 2 m/s. How high will the base of the swing rise above its original level...
March 20, 2007
Boats A and B leave the same place at the same time. Boat A heads due North at 12 km/hr. Boat B heads due East at 18 km/hr. After 2.5 hours, how fast is the distance between the boats increasing? You are looking at a right-angled triangle, let S be the distance between them ...
March 1, 2007
The radius of a sphere is increasing at a rate proportional to its radius. If the radius is 4 initially, and the radius is 10 after two seconds, what will the radius be after three seconds? dR/dt = c R Integrating this differential equation gives you ln R/Ro = c t R/Ro = e^(ct...
March 1, 2007
x/3=2 x=2*3 x=6 x/6=3 x=3*6 x=18 How would I get the missing number? ?/3 = 2 ?/6 = 3 What number divided by 3 will equal 2. Multiply 3 times two for the answer. Same for ?/6=3. what do u divide by to get 2 what u divide by to get 3
February 28, 2007
A worker pushes a 1500 N crate with a horizontal force of 345 N a distance of 24 m. Assume the coefficient of kinetic friction between the crate and the floor is .220. How much work is done by the floor on the crate? -M*g*(mu,k)*X Mg = 1500 N mu,k = 0.220 X = 24 m It is ...
February 27, 2007
A student pulls on a rope attached to a box of books with a mass of 35.0 kg and moves the box up a ramp at 12 degrees with the horizontal. If the box starts from rest at the bottom of the ramp and is pulled at an angle 25.0 degrees with respect to the inclince and with a 185 N...
February 24, 2007
The volume of a solid is given by V=pi x^2(lnx)^2. what is the approximate change in the volume when x is increased from 2.718 to 3.000? dv= PI 2x(lnx)^2 dx + Pix^2 *2lnx * 1/x reduce that. For x, use 2.718 dx= 3-2.718 check my thinking.
January 8, 2007