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Help Solving These Differential Equations

Help solving these differential equations please?

1. Use the method of undetermined coefficients to solve the following differential equation:

y '' + 4y = 4x.

Using the annihilator approach, I changed the equation to m^2 + 4 = 0, then getting m = 2i, -2i so my equation then became y = c1 cos 2x + c2 sin2x. My annihilator for the other side was D^2. After all my steps, my final answer was

y = 4+ x + c1 cos2x + c2 sin2x.

Can someone explain what the final answer is and what the correct one is please?


2. Find the solution of y '' - 6y' + 9y = 288 e^9t with y(0) = 3 and y'(0) = 5.

Thanks!

How to solve these Differential equations?

The equation of a curve is Y= 2cosX+sin2X
Find the x-coordinates of the stationary points on the curve for which 0
The curve Y= e^x + 4e^-2x has one stationary point

a) find the the Xcoordinate of this point

plz help...math is my worst subject :(

How do you solve this differential equation: y' = 1000 + 0.03y?

We need to separate the variables x and y. This becomes clearer if we write it as

dy/dx = 1000 + 0.03y.

We basically want all x and dx terms on the right, and all y and dys on the left. Now multiply each side by dx:

dy = (1000 + 0.03y)dx

And divide by the bracketed term:

dy/(1000 + 0.03y) = dx.

Now we can integrate both sides. int(dx) = x, so the RHS is easy. Now the left.

int(dy/(1000 + 0.03y)) = int(1/(1000 + 0.03y))dy.

We know from tables that int(1/(ax + b))dx = (1/a)*ln | ax + b |. So

int(1/(1000 + 0.03y))dy

= (1/0.03)*ln | 1000 + 0.03y |

= (100/3)*ln | 1000 + 0.03y |.

So we now have

(100/3)*ln | 1000 + 0.03y | = x + C.

Solve for y:

ln | 1000 + 0.03y | = (3/100)*x + A where A = (3/100)*C

1000 + 0.03y = Be^[(3/100)*x] where B = e^A

0.03y = Be^[(3/100)*x] - 1000

y = (1/0.03)*Be^[(3/100)*x]- 1000/0.03

= (100/3)*Be^[(3/100)x] - 100000/3.

So if we had an initial condition for y, we could find B and hence our particular solution. e.g. if we had y = y0 when x = 0, then

y0 = (100/3)*Be^[(3/100)*0] - 100000/3.

= (100/3)*B - 100000/3

So B = (3/100)*(y0 - 100000/3) = ... etc.

Please help me solve this differential equation such that y = pi/3 when x=1?

it is seperable
dy/dx = 1/x cot y
so
tany dy = 1/x dx
slip in an integral sign
∫tany dy = ∫1/x dx
ln|secy| = lnx + C
then y=pi/3 when x=1 gives
C = ln2
so
lnsecy = lnx + ln2 = ln(2x)
cosy = 1/(2x)
y = arccos[1/(2x)]

,.,.,.,.

Could u help me solve these 2 differential equation problems?

1.Determine complementary solutions using undetermined coefficients
a.d^4/dx^4 + 4(d^2y/dx^2) = 3x+sin2x

2.Determine the laplace transform of the following periodic functions.
a.f(t) = [sint 0 ≤ t < p ]
[ 0 p ≤ t < 2p ]
f(t) = f(t+2p)

How to solve these differential equations please?

1)
e^(-4z) dz = 2t dt

(-1/4) ∫(-4e^(-4z)) dz = ∫2t dt

(-1/4) e^(-4z) = t^2 + C

t = 0 --> z = 0
C = - 1/4

(-1/4) e^(-4z) = t^2 - 1/4
multiply both sides by (-4)

e^(-4z) = 1 - 4t^2

-4z = ln |1 - 4t^2|
z = (-1/4) ln |1 - 4t^2|


2)
dy/dx = x^5 y
dy/y = x^5 dx
ln y = (x^6)/6 + C
y = ke^((x^6)/6)
y(1) = 2
ke^(1/6) = 2
k = 2e^(-1/6)

y = 2e^(-1/6) e^((x^6)/6)
y = 2e^((x^6-1)/6)

How can I self study Differential Equations?

Gilbert Strang has done an amazing job making his instruction on several math topics including differential equations widely available for free[1]. He is an incredibly talented teacher. Back when I tutored Diff. Eq. I swore by Paul's online notes, which is an amazing reference for brushing up on topics quickly[2]. Also, check out the sage math website[3], it's a free desktop or online computing platform for solving and plotting problems that runs on a few different scripted language implementations. The key to getting your mind around diff. eqs. is to plot, plot, and plot again (at least for me).  Good luck and enjoy!Footnotes[1] http://math.mit.edu/~gs/dela/[2] Differential Equations[3] SageMath Mathematical Software System - Sage

What is the Solution of this differential equation?

The quotient rule d/dx(x/y) = [y -x(dy/dx)]/y^2Divide the eqn. by y^2[y-x(dy/dx ) ]/y^2 = cos x - sin x .cos xd(x/y)/dx = cos x - (1/2)sin(2x)d(x/y) = cosx dx - (1/2) sin 2x dx(x/y) = sin x +(1/4) cos 2x +cy = 4x/(4 sin x +cos 2x +k)

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