Why, when finding the area by definite integral, we have to find the indefinite integral first? As I understand, to find the area of under the curve, all we need is the equation of the curve. On the other hand, the indefinite integral helps us to find the original function from its derivative...
Homework Statement
How would I integrate exp(x)*cos(x), exp is referring to euler's number
Homework Equations
The Attempt at a Solution
u substitution doesn't work
Homework Statement
Integrate x^3sqrt(x^2+4)
The attempt at a solution
I have no idea how to substitute this integral in my favor. Can someone please set me on the right track? Thanks
I'm not sure if this is the write forum for this question, but I'm sure someone(maybe everyone) here knows the answer to my question. My question has to do with units and integration/differentiation. Does something "happen" to these units during these operations, or are you just supposed to...
\int{\left(\frac{x}{x^2 + 1}\right)\,dx}
how to integrate?
i know \int{\left(\frac{1}{x^2 + 1}\right)\,dx}
is tan^-1 x + C
how am i going to start answering this question
Homework Statement
If a car is going 30m/s and see's an accident 60 meters in front of him/her, at what deceleration must the car apply brakes in order to stop in time?Homework Equations
s(t) = \int(v)t
v(t) = \int(a)tThe Attempt at a Solution
So I know the physics equation that I could use for...
how do you integrate 1/(x2 + 1)2 ?
i have tried integration by partial fractions but when you set 1 equal to (Ax +B)(x2+1) + (Cx + D) this leads to A=B=C=0 and D=1 which just gives you the original equation
I am working on a problem (not homework) on diffusion and have landed up with an integral which I simply cannot integrate. No method seems to work.
I shall first describe the problem a little for you to check if I have landed up on the correct route, and then present the integral.
According to...
Homework Statement
What is integral of e^t (1+3sint)?
I tried integ by parts but its not working
Im familiar with the technique where you end up with two idental integrals on either side, then you add one side to the other, and divide by 2.
This isn't working though. Mainly because the RHS...
Homework Statement
Use trial wavefunction exp(-bx^2) to get an upper limit for the groundstate energy of the 1-d harmonic oscillator
The Attempt at a Solution
This is always going to give an integral of x^2*exp(-x^2). How do you do it? :/
I think I've done it at least once every day for the past week.
I week getting it wrong on the homework site.
Worst off all, it only alows 5 entries. I've used 4. Please help.
Homework Statement
Use separation of variables to solve (x+2y)y'=1 y(0)=2Homework Equations
u=2y+x >>I did not know how to start this, so i looked at the back of the book and it said to use that substitution
y=(u-x)/2, du=2dy+dx, dy=(du-dx)/2
The Attempt at a Solution
so i got the following...
Homework Statement
How do we evaluate integrals of COMPLEX-valued functions (like the following)?
2
∫ exp[-(2+3i)x] dx
0
This integral is appearing in my PDE course in the topic of Fourier transform, but I have no background of how to integrate complex-valued functions. Looking...
Homework Statement
integrate:
4*cos(n pi t) d(t)
Homework Equations
The Attempt at a Solution
is it: [4sin(n pi t)]/n.pi
or
[4t sin (n pi t)]/n.pi
any help very much welcome.
What does the following mean -
\int \textbf{F} \cdot d \textbf{r}
I know that its equal to work done. but i have problem in understanding it, what's the varibale. i am familiar with integrate cosxdx. what's is similar to dx in above equation. is it ds.
Now how can one get to this from above...
Dear all,
I would like to evaluate \int\frac{1}{1-2sin\left(x\right)}dx
Firstly, I make use of the Weierstrass substitution method by letting:
u=tan\left(\frac{x}{2}\right)
and therefore
sin\left(x\right)=\frac{2u}{1+u^{2}}
and
dx=\frac{2}{1+u^{2}}du
Eventually I can...
Homework Statement
I'm a little confused with this integral:
\int^\infty_{-\infty}e^{-a|x|}\,dx
Homework Equations
The Attempt at a Solution
Now, I believe the typical way to evaluate this is to say, hey, because of the |x|, this thing is symmetric about the x axis, and so we can...
Homework Statement
I am losing my first year calculus skills :(
I don't remember how to integrate x5 exp(x2).
What is the fastest way?
Homework Equations
N/A
The Attempt at a Solution
Maybe we need to integrate by parts? But how should I set u and dv?
Thanks for any help!
Hi there,
I am having a hard time figuring out how to integrate cos(2x)^N where N=0,1,2...
Can anyone give me and hints/tips on how to go about integrating this?
Thanks!
Homework Statement
Define the function over the four intervals in order to find the area under the curve from [-4,6].
To do so, find the equations of the line and circle, using the data in the graph.
Homework Equations
None?
The Attempt at a Solution
To be honest, there...
Homework Statement
In a sphere of radius R, the charge density varies as \rho(r) = BrN. There is no charge outside the sphere. B and N are constants.
a.) Find the charge enclosed in a sphere of radius r<R.Homework Equations
\rho=dq/dvThe Attempt at a Solution
I integrated \rho(r)(4\pir2dr)...
Hi,
the question is integrate x^2 /square root (x^2 +1).
I tried to do it but i was stucked in the very last step.at the end,I got x/2 * cosh(arcsinh x) + 1/2 * arcsinh x - arcsin (square root (x^2 + 1)) +C. I dunnoe how can I simplify cosh(arcsinh x) into simplier form in term of x. I hope...
How can you intgertate the 1/cos(x)?
The right answer can be found in Wolfram alpha at http://www.wolframalpha.com/input/?i=1%2Fcos(x)
My first wrong answer was ln(cos(x)).
It suggests me that you cannot use the rule, ln(x), for trigonometric functions
1.a Evaluate the following. Show all work.
http://img90.imageshack.us/img90/289/problemu.png
1.b Differentiate.
http://img293.imageshack.us/img293/1440/problem2.png
Homework Equations
ƒ b-a f(x)-g(x)
The Attempt at a Solution...
Homework Statement
Find \int{tan^2xsec^2xdx}
Homework Equations
tan^2x=sec^2x-1 (1)
The Attempt at a Solution
Using (1): \int{(sec^4x-sec^2x)dx}
Now, \int{sec^4xdx}-\int{sec^2xdx}=\int{sec^4xdx}-tanx+c
I can't figure out how to solve \int{sec^4xdx} though.
Homework Statement
The whole expression is
\frac{(-1)^n (2n)!}{2^{2n} (n!)^2} \int^{1}_{-1} (x^2-1)^n dx
and the answer should be
\frac{2}{2n+1}
but I don't know how to get there.
I came across this while checking the orthogonality of the associated Legendre functions.
Homework...
Dear all,
i met a problem that i couldn't get the on axis field of a finite solenoid that integrating from a thin shell solenoid equation.
The thin shell equation link:
http://www.netdenizen.com/emagnet/solenoids/thinsolenoid.htm
And the on axis finite solenoid equation link...
Hi everyone,
Can you tell me how to integrate the following equation?
\int\frac{1}{x^2 + 1} \ dx
I've tried the substitution method, u = x^2 + 1, du/dx = 2x. But the x variable is still exist.
Also, the trigonometry substitution method, but the denominator is not in \sqrt{x^2 + 1}...
Homework Statement
\frac{dx}{(4+x^2)^2}Homework Equations
I understand that \frac{dx}{a^2+u^2} = \frac{1}{a} tan -1 \frac{u}{a} + cThe Attempt at a Solution
The extra square is throwing me off for some reason. If I let a=2 and u=x it doesn't seem to help because of the whole term being...
Homework Statement
Integrate x^5sin(x^3). Using Integration by parts.
The Attempt at a Solution
I don't know which one to take du and u
can anyone please help me out?
Thanks a lot before hand!
Homework Statement
Integrate Sqrt[ ex+1]
2. The attempt at a solution
I first multiplied the equation by e^x / e^x, then tried substitution, with
u = e^x + 1
du = e^x dx
This gave me: Integral 1/(u-1) * (u)^1/2 du
However, I'm stumped at this part. Substitution here doesn't...
Homework Statement
integrate: e(x^2 +x)(2x+1) dx
The Attempt at a Solution
let u= e(x^2 +x)
du=e(x^2 +x)(2x+1)dx
integral e(x^2 +x)(2x+1) dx = integral 1/u du
am I on the right track? i didnt get the same answer as the prof...
Homework Statement
I am having trouble solving the following:
\intsin(lnx) dx
The Attempt at a Solution
I let u = ln x but this makes xdu = dx so I am left with
\intx sinu du
Homework Statement
Integrate (a^x + b^x)^3 /((a^x)*(b^x))
The Attempt at a Solution
I have only 2 semesters of calculus under my belt yet nothing in my experience has taught me to do anything like this
Homework Statement
I have to solve the following integral
1/(sqrt[x] * ln[x]) from 2 to infinity
Homework Equations
The Attempt at a Solution
u= ln[x] dv=1/sqrt(x)
du= 1/x v= 2 sqrt(x)
If I do this I get
lim (ln b/ sqrt[x] - 4 sqrt[x] -...
Homework Statement
The problem states: Use substitution to solve:
y'=1/(x+y)^2-1Homework Equations
The Attempt at a Solution
I used the substitution of v=x+y
resulting in the answer y=[3(x-C)]^(1/3) - x
but I'm not too sure that's right
Can some help with the answer and the steps for...
Homework Statement
Compute the Fourier cosine series for given function:
f(x)=sinx 0<x<piHomework Equations
for cosine series of f(x) on [0,T]... use this general equation:
http://mathworld.wolfram.com/FourierCosineSeries.html
The Attempt at a Solution
so I get:
a0 = (2/pi) *...
Hi! I'm having trouble understanding my textbook, so can someone please explain to me how they got from
\int1/(1+x)2 dx, with the range of the integral from 0 to x/n
to
1 - n/(x+n)
THank you So MuCh
Homework Statement
When I plug in
Integrate[ x/(1 + x), x]
into Mathematica, I get
x - Log[1 + x]
which I've been able to recreate on paper. However, when I plug in
Integrate[ 2 x/(1 + 2 x), x]
I get
1/2 + x - 1/2 Log[1 + 2 x]
but on paper I get
x - 1/2 Log[1 + 2...
Homework Statement
convert double integral from line one to polar integral and then evaluate
see problem 12 attachment
Homework Equations
y=rsinx
x=rcosx
r^2=x^2+y^2
The Attempt at a Solution
see problem 12 attachment
I calculate a area of zero. are my limits wrong and if...
Homework Statement
4\int 1/ ( x^3 *( 1 - x^2)) dx
Homework Equations
Maybe integration by parts?
The Attempt at a Solution
This is actually a small fragment of a very large, long problem but, I cannot for the life of me think how to integrate this with there being a product...