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#1451 Re: Jokes » Math Pick-up Lines » 2015-08-30 09:09:54

bob bundy wrote:

I once used set theory in a wedding speech, but the couple were both mathematicians, conveniently having last names beginning with A and B respectively. I wouldn't recommend it in a chat up line.

Bob

How about as a complement instead?

#1453 Re: Help Me ! » Integration by Parts with natural logs » 2015-08-30 08:51:24

Everything looks good up to this point:

jubadedo wrote:

Then I plugged in the bounds and got

You made a small mistake when plugging in the bounds.

#1454 Re: Help Me ! » Asap please need the answer » 2015-08-30 08:42:35

denis_gylaev wrote:

Wait is the question really trivial or am I missing something

Derrick: 0
Ari: 0.50
Wesley: 2.10

That's probably the best answer for the question as given.

#1458 Re: Help Me ! » questions from integration » 2015-08-28 21:07:29

Let u = sin(x) and express sin(3x) in terms of sin.

#1462 Re: Help Me ! » Definite Integrals of Inverse Functions » 2015-07-25 07:51:19

Agnishom wrote:

If I know the coordinates of C,  yes

You know x. So what's f(x)?

#1463 Re: Help Me ! » Definite Integrals of Inverse Functions » 2015-07-25 07:14:28

There are other ways of finding areas besides integration.

#1464 Re: Help Me ! » Definite Integrals of Inverse Functions » 2015-07-24 22:52:09

bobbym wrote:

Hi;

I am getting:

I agree with your answer.

#1466 Re: Help Me ! » Quick question on sequence convergence. » 2015-07-23 06:21:03

Yes, a sequence does not converge if it converges to two different values (i.e. it diverges). Here, your sequence given by

has two subsequences which converge to two different values depending on whether or not n is odd or even.

You can try constructing a proof by contradiction of what happens when you suppose a sequence converges to two different limits.

#1467 Re: Help Me ! » Definite Integrals of Inverse Functions » 2015-07-23 05:34:12

Correct. You should be able to complete the problem now, with your answer of the form you wrote in your original post.

#1468 Re: Help Me ! » Definite Integrals of Inverse Functions » 2015-07-23 01:52:26

It seems that you can't get anything helpful from the limits of integration (in particular, f-¹(π/2) isn't that helpful). So try the geometric approach, which seems much easier:

-Plot a graph of f(x).
-Look at the area you're trying to compute.
-Can you see how to integrate the inverse function without finding it explicitly? (How would you graph f-¹(x) given the graph of f(x)?)

#1469 Re: Help Me ! » Definite Integrals of Inverse Functions » 2015-07-21 00:56:48

There are two ways to do this problem: geometrically or algebraically. (The former will give you a better idea of what's going on.)

For a geometric approach, try plotting a graph of your function and looking at which parts of the picture correspond to which integrals -- in particular, the area for your inverse function.

For an algebraic approach, make a substitution like x = f(t).

#1470 Re: Help Me ! » Vectors » 2015-07-21 00:50:06

For (1), you've got to show that there exists a straight line passing through each of those points. Try looking at the difference between 4i + 5j and 3i + 3j.

For (2), the body is moving 2i - 3j metres every second, i.e. it moves 4i - 6j after 2 seconds, 6i - 9j metres after 3 seconds, and so on.

For (3), since this is a two-dimensional problem, you might find it helpful to simply plot i - j in Cartesian co-ordinates.

For (4), what are the possible values of b?

For (5) (a), speed is the magnitude of the velocity vector. So what's the magnitude of i + 3j?

For (5) (b), apply what you've done in (2).

Ditto for (5) (c).

#1471 Re: Exercises » Complex Analysis » 2015-07-20 00:36:51

No problem, I can post the solutions to others if you would like. #6 is basically a generalisation of the method used in post #14.

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