Thursday

August 25, 2016
Number of results: 125,283

**Differential Equations**

Classify the following differential equations as linear or nonlinear: 3x' +5x=7t^2 4x^2+2x+5tx=0
*September 11, 2014 by Connor*

**Differential Equations!**

I'm struggling solving this separable differential equations: (du/dv) = ((uv+u)/(uv+v)) I multiplied both sides by dv to get on the left side just du and cancel out dv, but after that don't know where to go. I've tried integration by parts but it doesn't look right! Any help ...
*January 13, 2013 by Massiel*

**Differential Equations**

in this problem we consider an equation in differential form M dx+N dy=0 (2y-2xy^2)dx+(2x-2x^2y)dy=0 give implicit general solutions to the differential equation. F(x,y)=
*February 15, 2016 by Anonymous*

**Math**

A two population model is satisfied by a system of differential equations given by, V(x,y) = (ax,by)^T The general solution of the system of differential equations has x = áe^at for some constant á. The parameter t can be eliminated and we can express y in terms of x in the ...
*August 25, 2012 by Anonymous*

**differential equations**

solve the differential equation by seperation of variables 5. y'=xy/2ln y
*March 17, 2011 by cathy*

**Differential Equations**

Solve the seperable differential equation for U. du/dt = e^(5u+7t) - Using the following initial condition U(0) = 12
*August 27, 2011 by Kody*

**Differential Equations**

Solve the differential equation below with initial conditions. Compute the first 6 coefficient. Find the general pattern. (1-x)y"-y'+xy=0 y(0)=1, y'(0)=1
*July 9, 2012 by Jason*

**Differential Equation**

Hello everyone. I was wondering if anyone knows a site that could help me with the homework free online...with Differential equations. it would be great. I need help on in big time thank you
*October 22, 2008 by mary*

**calculus**

is y = x^3 a solution to the differential equation xy'-3y=0?? how do i go about solving this??? also, is there a trick to understanding differential equations? i'm really struggling with this idea, but i'm too embarassed to ask my professor for help.
*December 1, 2008 by Kenneth*

**Differentail Equations**

I cant figure out how to do this type of problem! Consider the first order differential equation y′+(x/(x^2−4))y=(e^x)/(x−9) For each of the initial conditions below, determine the largest interval a<x<b on which the existence and uniqueness theorem for...
*June 6, 2015 by Eric*

**differential equations **

Consider the 2nd order differential equation: x''(t)=-x-A(x^2-1)x'(t) x(0)= 0.5 x'0)= 0 ''= 2nd order,'= 1st order where A is a positive constant.As the value of A increases this equation becomes increasingly stiff. Convert this equation to two first-order equations. please ...
*November 16, 2011 by Rikki *

**Math**

I need to solve this set of differential equations {y'+(t/2)1, y(0)=1} and then find the limiting value as t approaches infinity. I'm not sure where to start. I found the answer to the differential equation to be: y(t)=e^-t^2/4[e^(r^2/4)dr +Ce^(-t^2/4)where the [ sign ...
*September 6, 2012 by Emily*

**Differential Equations**

Find the general solution of the differential equation specified. 1) dy/dt= 1/(ty+1+y+1) 2) dy/dx=sec y I got y(x)=arcsin(x) for the second one. I'm not sure what to do with the first one.
*January 22, 2013 by Erica*

**PLEASE HELP WITH DIFFERENTIAL EQUATIONS QUESTION??**

Which of these equations have an equilibrium solution. What are they? How are their DE's different? dy/dx=6y-y^2 dy/dx 15-3y
*December 3, 2014 by Francine*

**Differential Equations**

The velocity v of a freefalling skydiver is well modeled by the differential equation m*dv/dt=mg-kv^2 where m is the mass of the skydiver, g is the gravitational constant, and k is the drag coefficient determined by the position of the driver during the dive. (a)Find the ...
*January 24, 2013 by Erica*

**calculus**

Can you give me a good website on the topic, slope fields and differential equations? I need to match six slope fields with the correct differential equation. 1. dy/dx=x-y 2. dy/dx=1+x 3. dy/dx=cosx 4. dy/dx=2x 5. dy/dx=x+y 6. dy/dx=y(2-y)
*November 7, 2007 by Anonymous*

**ordinary differential equation**

Solve the simultaneous differential equations L(di1/dt)+Ri1+(1/2)L(di2/dt)=E L(di2/dt)+Ri2+(1/2)L(di1/dt)=0 where 𝐿, 𝑅, and 𝐸 are constants and given that i1=i2=0 when t=o
*May 21, 2016 by thigan*

**Ap Calculus**

Ok, I've been doing BC review tests to prepare for the AP exam. I came across this free response problem and I have no idea how to do it, can someone please help me with this? It gives the differential equations: dP/dt = .03P(30-P) and it asks "Find the general solution to the...
*April 25, 2007 by Jessica*

**Differential Equations**

Consider the differential equation: dy/dt=y/t^2 a) Show that the constant function y1(t)=0 is a solution. b)Show that there are infinitely many other functions that satisfy the differential equation, that agree with this solution when t<=0, but that are nonzero when t>0...
*January 31, 2013 by Erica*

**Differential Equations**

Consider the differential equation: dy/dt=y/t^2 a) Show that the constant function y1(t)=0 is a solution. b)Show that there are infinitely many other functions that satisfy the differential equation, that agree with this solution when t<=0, but that are nonzero when t>0...
*January 31, 2013 by Erica*

**Differential Equations**

Consider the differential equation: dy/dt=y/t^2 a) Show that the constant function y1(t)=0 is a solution. b)Show that there are infinitely many other functions that satisfy the differential equation, that agree with this solution when t<=0, but that are nonzero when t>0...
*January 31, 2013 by Erica*

**math**

Solve the following ordinary differential equations. I) (2y+x^2+1)dy/dx+2xy-9x^2=0 ii) d^2/dx^2+3day/DX+2y=x^2
*March 20, 2015 by gourav *

**math-differential equations**

hi i need to know how to do this one thanks Find the solution to yx + x + (dy/dx) = 0 ; y(9) = -9 y = ???? Does this separate the variables? dy/dx=-x(y+1) dy/(y+1) = -x dx
*August 5, 2007 by kayla*

**University, Engineering Math**

solve the ffg. differential equations: 1. x^3 +(y+1)^2 dy/dx=0 2. dy/dx-(1+1/x)y=y^2 3. dy/dx + ytanx=y^3sec^4x
*February 5, 2013 by Taldil*

**differential equations**

Convert x''+ sin(x) = 0 into a first order system of equations. (x'' refers to the second derivative of x). I tried: y1 = sin(x) y2 = x' {y1' = cosx {y2' = -sinx Not sure if I did it right.
*November 25, 2015 by Sarah*

**Differential Equations**

Consider the system shown below of two masses of mass m, coupled together between two fixed walls via springs with varying spring constants. Let x(t) and y(t) be the horizontal displacements of the two masses as a function of time. (a)Write down a system of differential ...
*October 13, 2014 by Smith*

**Math**

Are the differential equations separable or not? 1. y'= ye^(x+y) 2. y'= ye^(xy) 3. y'= y(xcos(y)) If they are, could you show how? Any help, even on one, would be extremely appreciated!
*February 2, 2011 by Leah*

**Calculus**

dy/dx = 4ye^(5x) a) Separate the differential equation, then integrate both sides. b) Write the general solution as a function y(x). For the second part, I got y(x)=e^((5e^(5x))/(5)) + C but I don't understand how to separate differential equations and/or integrate both sides...
*June 16, 2014 by Jamie*

**Differential Equations**

A rabbit starts at the origin and runs up the right branch of the parabola y=x^2 with speed a. At the same time a dog, running with speed b, starts at the point (c,0) and pursues the rabbit. Write a differential equation for the path of the dog
*January 26, 2012 by Samantha*

**Math**

The maximum number of arbitrary constants is equal to a. Number of derivatives in the differential equation b. Degree of differential equation c. Order of differential equation e. None of the above I don't understand this, but my guess it's letter A. Please help.
*September 13, 2014 by Rin*

**math- differential equations**

This is what im given (1 + x)dy/dx - xy = x + x2 ____________________________________________________________________________________________________________________________________________________________ From my understanding I should move everything to one side like: (1 + x...
*September 7, 2007 by manny*

**Differential Equations**

(x^2+1)dx+x^2y^2dy=0 need help:)..thanks.
*July 14, 2014 by Alyanna*

**Differential Equations**

(D^2 + 1) y = sec^2 2x solve for Yp.
*October 14, 2014 by Cathy*

**Differential Equations**

(D^2 + 1) y = sec^3 x solve for Yp.
*October 14, 2014 by Cathy*

**Differential Equations**

(D^2 + 1) y = 1/(1 + sin x) solve for Yp.
*October 14, 2014 by Cathy*

**Differential Equations**

Solve x(dy/dx)=(y^2)/(1-y log x).
*August 3, 2015 by Ranajoy*

**Differential Equations**

(D^2 + 1) y = sec^2 (x) tan (x) solve for Yp.
*October 14, 2014 by Cathy*

**differential equations**

rk4 method with h 0.1 solve for y' = 4x-2y, y(0)= 2; y(0.5)
*August 3, 2016 by Carol*

**calculus-differential equation**

Consider the differential equation: (du/dt)=-u^2(t^3-t) a) Find the general solution to the above differential equation. (Write the answer in a form such that its numerator is 1 and its integration constant is C). u=? b) Find the particular solution of the above differential ...
*February 5, 2008 by Jeff*

**Calculus**

Are the following differential equations separable or not? * y'= ye^(x+y) * y'= ye^(xy) * y'= y(xcos(y)) I am no good at these :[
*February 2, 2011 by Grace*

**Calculus AB**

Verify if the given equations are solutions to the differential equation. dy/dt=k(y-a) i) y=1-ae^(kt) ii) y=a+Ce^(kt)
*February 28, 2011 by dyingincalc*

**Differential Equations**

Find the eigenvalues and eigenfunction for the BVP: y ' ' '+ λ2 y ' = 0 , y(0) = 0, y’(0) = 0 and y’(L) = 0
*April 22, 2012 by Chuck*

**maths-urgently needed[Differential equations]**

solve- dy/dx = 2xy + (y^2/x^2)
*February 7, 2013 by Anonymous*

**maths-urgently needed[Differential equations]**

solve- dy/dx = 2xy + (y^2/x^2)
*February 7, 2013 by Anonymous*

**differential equations**

the general solution of the diff. eq. y' = (1/x)(y/(1-y)) - (1-x)(y/(1-y)) in implicit form is?
*August 4, 2015 by Anonymous*

**Math: Differential Equations**

I've been stuck on this math hw problem for a while, I was thinking of taking the integral of the equation, but I've been messing up too much that I'm not sure anymore. Q: Is it possible to solve y'=x/(x^(2)-1) for y(1) = 0? Thank you!
*January 15, 2014 by Student*

**calculus**

solve the differential equations subject to the given conditions. dy/dx= 4x^1/2 y=21 of x=4 is this derivative?!
*July 21, 2012 by Anonymous*

**Differential Equations**

y'=2x+y. Find a solution whose graph is also an isocline.
*February 14, 2013 by Brian*

**Differential equations in Calculus...plsssss help?**

Suppose that represents the temperature of a cup of coffee set out in a room, where T is expressed in degrees Fahrenheit and t in minutes. A physical principle known as Newton’s Law of Cooling tells us that dT/dt = -1/15T+5 15T + 5. a) Supposes that T(0) = 105. What does the ...
*November 30, 2014 by Bridget*

**Differential Equations (Another) Cont.**

For the following initial value problem: dy/dt=1/((y+1)(t-2)) a)Find a formula for the solution. b) State the domain of definition of the solution. c) Describe what happens to the solution as it approaches the limit of its domain of definition. Why can't the solution be ...
*January 31, 2013 by Erica*

**ordinary differential equation**

consider the differential equation d^3x/dt^3 - 9(d^2x/dt^2)+ 27(dx/dt) -27x = c0s t +sin t + te^(3t) a) show that characteristic equation of the differential equation is (m-3)^3 =0 (b) Hence, find the general solution of the equation.
*May 21, 2016 by thigan*

**differential equations**

dy/dx=4x/y..verify that the straight lines y=2x are solution curves, provided x doesnt equal 0.
*January 9, 2013 by siddh*

**mathematics **

Solve the following differential equations: (I). Cos x dy/dx + ysin x= sec^2 x (II). Y"-10y' + 41y=0
*June 27, 2014 by mitesh*

**Differential Equations**

(a) Let S be the set of solutions y(t) to the differential equation dy/dt = -y for t> 0. With addition and scalar multiplication of elements defined in the usual way, is S a vector space? (b)Let T be the set of solution y(t) to the differential equation dy/dt = 1 - y for t...
*October 13, 2014 by Cam*

**math**

Can someone please explain this problem Find the general solution to the linear system of differential equations. x'1 x'2 x'3 = −4 −4 5 0 −4 4 0 4 2 x1 x2 x3
*April 25, 2015 by Anonymous*

**math (differential equation)**

show that y sub n=cos(ncos^-1(x)) satisfies the differential equation: (1-x^2)(d^2y/dx^2)-x(dy/dx)+n^2(dy/dx)=0
*March 3, 2013 by shoosh*

**Calculus - Second Order Differential Equations**

Posted by COFFEE on Monday, July 9, 2007 at 9:10pm. download mp3 free instrumental remix Solve the initial-value problem. y'' + 4y' + 6y = 0 , y(0) = 2 , y'(0) = 4 r^2+4r+6=0, r=(16 +/- Sqrt(4^2-4(1)(6)))/2(1) r=(16 +/- Sqrt(-8)) r=8 +/- Sqrt(2)*i, alpha=8, Beta=Sqrt(2) y(0)=2...
*July 10, 2007 by COFFEE*

**Differential Equations**

a) Sketch the phase line for the differential equation dy/dt=1/((y-2)(y+1)) and discuss the behavior of the solution with initial condition y(0)=1/2 b) Apply analytic techniques to the initial-value problem dy/dt=1/((y-2)(y+1))), y(0)=1/2 and compare your results with your ...
*February 3, 2013 by Erica*

**Math: Differential Equations**

I'm given y''= sin(x) with the initial conditions of y(0)=0 and y'(0)=2. I've already taken the integral two times to get an answer of y= -sin(x)+3x, however, I'm stuck as to how to make this equation in terms of x=... Please explain, I'd really appreciate it!
*January 14, 2014 by Student*

**Differential Equations**

Use the Laplace Transform to solve this initial value problem. y'''' - 8y = 0, y'(0)=63, y''(0)=216, y'''(0)=297 I would really appreciate the help.
*November 25, 2013 by Emily*

**Math, Calculus**

help Please... Differential Equations Problems... please give the complete solution, so that i can understand how it is derived... tnx in advance, god Bless... Here are the problems : 1.) y dx + (2x+3y)dy = 0 2.) (2xy + y^(2) ) dx - 2x^(2) dy = 0 ;y = e, x = e 3.) y( x^(2) + ...
*October 19, 2009 by Huck*

**Differential Equations**

a) Sketch the phase line for the differential equation dy/dt=1/((y-2)(y+1)) and discuss the behavior of the solution with initial condition y(0)=1/2 b) Apply analytic techniques to the initial-value problem dy/dt=1/((y-2)(y+1))), y(0)=1/2 and compare your results with your ...
*February 3, 2013 by Erica*

**Math**

Find the specific solution for the following differential equations: a) (dy/dx)^2 - x^4 = 0 given the initial value y(1) = 0 b) dy/dx = ysinx given the initial value y(pi) = 1
*November 9, 2008 by Alice*

**MATH **

Solve the differential equations? (calculus) a) square root cotany/ (1+x^2)sin^5y dy/dx = e^x^3 +3x/ square root cotany b) y^2/cosx dy = e^sinx/ e^y^3-1 dx
*May 8, 2013 by RAY*

**Calculus Please help!**

The differential of the function y=(x^2+6)^3 is dy=______dx. When x=2 and dx=0.05, the differential dy=_______? A) dy=______dx? B) the differential dy=_______?
*February 28, 2014 by ALI*

**Calculus**

Integrate e^(-x^2/2) dx What branch of calculus is this? Is this differential equations?
*March 7, 2008 by mathstudent*

**Help with differential eqs problem???? (Calculus)**

Consider the differential equation dy/dt=y-t a) Determine whether the following functions are solutions to the given differential equation. y(t) = t + 1 + 2e^t y(t) = t + 1 y(t) = t + 2 b) When you weigh bananas in a scale at the grocery store, the height h of the bananas is ...
*November 30, 2014 by Stacey*

**Math**

help Please... Differential Equations Problems... please give the complete solution, so that i can understand how it is derived... tnx in advance, god Bless... Here are the problems : 1.) y dx + (2x+3y)dy = 0 2.) (2xy + y^(2) ) dx - 2x^(2) dy = 0 ;y = e, x = e 3.) y( x^(2) + ...
*October 18, 2009 by Huck*

**PLEEEEEAAAASE HELP WITH DIFFERENTIAL EQ PROBLEMS!!**

1) What are the equilibrium solutions to the differential equation and determine if it is stable or unstable with the initial condition y(-4)=1: 0.1(y+2)(4-y) 2) Use Euler's method with step size=0.5 and initial condition y(0)=3 to solve the equation y(0)=3 to estimate y(2), ...
*December 8, 2014 by Karen*

**Calculus **

Find the particular solution of differential equations that satisfies the initial condition dx/dy=e^(x+y) x(1)=0 I know you have to get all the y and dy on one side and x and dx on the other so you can intagrate and stuff, but im having trouble getting there
*May 18, 2016 by Arie*

**college differential equations**

Find two linearly independent power series solutions to the diffrential equation. State the first 3 therms of each series: 2x^2y''+xy'-(1+2x^2)y=0
*July 28, 2010 by Justin*

**Differential Equations**

Solve dy/dx = y/(2y-x) using rational substitution (using v=y/x) with the initial condition y(0)=1. I solved this problem and found C (the constant) to be undefined. That is not the correct answer.
*February 15, 2014 by Liz*

**Math: Differential Equations**

Solve the initial value problem y' = y^2, y(0) = 1 and determine the interval where the solution exists. I understand how the final solution comes to y = 1/(1-x), but do not understand how the solution is defined from (-infinity, 1) and not (1, infinity).
*October 9, 2014 by Anonymous*

**math**

a bank account earns 7% annual interest compounded continuously. you deposit $10,000 in the account, and withdraw money continuously from the account at a rate of $1000 per year. a. write the differential equation for the balance, B, in the account after t years b. what is the...
*March 14, 2011 by Anonymous*

**Calc 2 college**

Modeling with differential equations. If a bacteria culture doubles every 10 minutes and the original culture has 300 cells determine the rate of growth.
*July 9, 2010 by Marianne*

**Math**

For the harmonic potential V(x,y) = x^2 + y^2 a) Find the total differential, dV. For this I got dV = 2x.dx + 2y.dy b) Given that -dV = F(x).dx + F(y).dy, where F(x) and F(y) is the force in the x and y direction, respectively, write a differential equation describing the ...
*November 18, 2008 by Beth*

**Differenctial equations**

Use the change of variable x = exp(s) to recast the differential equation xy′′+y′+(L/x)y=0 Please HELP ME
*October 14, 2011 by lili*

**MATH**

Differential equations, initial value problem. The general equation of motion is: mx"+Bx'+kx=f(t), where the independent variable is t, and the displacement x is the dependent variable. In this case, external force f(t)=0, so mx"+Bx'+kx=0 substitute m=0.25, k=4, B=1 we have a ...
*March 16, 2011 by Anonymous*

**Math 116**

Consider the following system of equations. y=2x-2 y-2x=9 What can you conclude about the system of equations? a. The system of equations is inconsistent. b. The system of equations is dependent. c. The system of equations is independent. d. none of these.
*June 21, 2013 by Queta*

**college math/chemistry**

chemical reaction: E + S <=> E~S <=> E-S <=> indicates a bidirectional reaction with different forward and backward rate constants. we can call these k1, k2, k3 and k4 in the above equation. Here, the enzyme binds to the substrate; the initial complex E~S ...
*December 9, 2010 by Heather*

**math**

The displacement s (in metres) of a body in a damped mechanical system, with no external forces satisfies the following differential equation: 6 3 2 2 dt ds dt d s where t represents time in seconds. If at time t = 0, s = 0 and 5 dt ds m/s, ...
*May 17, 2011 by Karl Haxell*

**math **

Let y = tan(5x+2). Find the differential dy when x = 2 and dx = 0.4 Find the differential dy when x = 2 and dx = 0.8
*March 28, 2012 by bobby*

**Math**

Let y = sqrt(7-x) Find the differential dy when x= 1 and dx = 0.4 Find the differential dy when x= 1 and dx = 0.02
*December 18, 2014 by Anonymous*

**Math 1**

Consider the following system of equations. y = 4x - 4 y - 4x = 3 What can you conclude about the system of equations? A) The system of equations is inconsistent. B) The system of equations is dependent. C) The system of equations is independent. D) none of these
*October 20, 2013 by sam*

**math**

Consider the following system of equations. y = 2x - 2 y - 2x = 7 What can you conclude about the system of equations? The system of equations is inconsistent. The system of equations is dependent. The system of equations is independent. none of these
*September 8, 2014 by robert*

**calculus differential equation**

Find in implicit form the general solution of differential equation dy/dx=2(e^x-e^-x)/y^2(e^x+e^-x)^4 with (y>0). I know this requires a seperation of variables but I beyond that I am confused by how.Thanks.
*February 12, 2011 by malcolm*

**calculus differential equation**

Find in implicit form the general solution of differential equation dy/dx=2(e^x-e^-x)/y^2(e^x+e^-x)^4 with (y>0). I know this requires a seperation of variables but I beyond that I am confused by how.Thanks.
*February 12, 2011 by malcolm*

**Calculus **

Which of the following is a separable, first-order differential equation? A) dy/dx= x+y/2x B) dy/dx=x+y/x-y C) dy/dx=sinx << D) dy/dx=xy/x+y E) dy/dx= 2lnxy 2) The differential equation dy/dx=y/x^2 has a solution given by: A) y=C sqrt(x^2+4) B)y=C e^-1/x C)-1/2ex^2+C D) ...
*May 8, 2014 by Samantha*

**Calculus**

Consider the differential equation dy/dx=xy-y. Find d^2y/dx^2 in terms of x and y. Describe the region in the xy plane in which all solutions curves to the differential equation are concave down.
*May 1, 2014 by Michelle*

**math numerical methods**

Consider the following second order differential equation: y"-2x^(2)y+y^(3)=17cos(4x) with y(0)=4 , y'(0)=-9 If we let u=y and v=y′ then as an AUTONOMOUS first order system, the second order differential equation is correctly expressed as:
*April 21, 2013 by mahdi*

**Math**

a weight of mass m is attached to a spring and oscillates with simple harmonic motion. By Hooke's Law, the vertical displacement, y(t) satisfies the differential equation dy/dt=sqrt(k/m)*sqrt(A^2-y^2) where A(Fixed) is the maximum displacement and k is a constant, solve this ...
*December 15, 2012 by A.J.*

**DIFFERENTIAL EQUATION**

find the differential equation of family of lines with slope and y intercept equal.
*June 16, 2012 by JAJA111111*

**Differential Equations **

A government agency has a current staff of 5000, of whom 25% are women. Employees are quitting randomly at the rate of 100 per week. Replacements are being hired at the rate of 50 per week, with the requirement that half be women. Interested in the rate of women coming in and ...
*October 30, 2012 by bryant*

**Differential Equations**

solve using variation of parameters: y"+36y=[csc(6t)]^2 I don't understand variation of parameters very well at all.
*April 24, 2012 by Rosy*

**math**

What is the name for the partial differential symbol (∂)? I see some papers use greek lowercase delta instead (δ) where I believe they are implying a partial differential. Is this normal? Is there supposed to be a conceptual difference between the two symbols? Or is...
*February 6, 2009 by anonymous*

**Differential Calc**

If: 0 = f(1) = a+b+c+d 2 = f(-2) = -8a+4b-2c+d 0 = f'(1) = 3a+2b+c 0 = f'(-2) = 12a-4b+c "since we now have four equations and four unknowns, we can determine unique solution. Solving for "a" and "b", a=, b=" Please show the steps, I am so confused and no one knows how to do ...
*November 5, 2012 by Joey*

**Calc 2**

Differential equations. There are gophers in a very large vacant lot. The original population is 30 Gophers. After 2 months there are 38. When will there be 45 gophers? round answer to nearest tenth of a month
*July 9, 2010 by Scott*

**Differential Equations**

Consider the spring - mass system, shown in Figure 4.2.4. consisting of two unit masses suspended from springs with spring constants 3 and 2, respectively. Assume that there is no damping in the system. Show that the displacements u1, and u2 of the masses from their respective...
*May 13, 2014 by Daoine*

**math**

10. Sales of televisions grow at a rate proportional to the amount present (t is measured in days). (a)Set up a differential equation to model this problem. (b)Solve the differential equation if at t = 0, there are 20 televisions sold and after 3 days, 500televisions are sold.
*May 31, 2007 by dougal*

**Physics**

For the harmonic potential V(x,y) = x^2 + y^2 a)Find the total differential, dV. b) Show that dV is exact c) Given that -dV = Fx.dx + Fy.dy where Fx and Fy is the force in the x and y direction, respectively, write a differential equation describing the change of potential ...
*November 14, 2008 by Beth*