This is here for people to ask questions regarding their homework, and the more educated members of the community to answer.


That is all.

here's an answer to just about any math problem, and half of science while yer at it.

http://www.wolframalpha.com/

Anyone here taken a Mathematical Analysis class? Either Intro or Complex? Some of the shit blows my mind.

ie:

6. (5 pts) Give an example of a function f : R → R that is bounded and continuous on all of R but does not attain its maximum or its minimum anywhere on R.

~BD

Edit: Answered f(x) = Arctan(x)

f(x) = arctan(x)

Basically anything that approaches its maximum and minimum values as x goes to ± infinity.

what would it mean if it isnt bounded?

Not sure what you mean. If you remove the boundedness condition, the question is even easier. For example, f(x) = x is a continuous function on R that does not attain its maximum or minimum values.

More generally, it's always possible to find a function of this kind if its domain is not a closed and bounded subset of R. Such subsets are called compact and have many nice properties. R itself is not a bounded subset (although it is trivially closed), which is why functions of this kind exist. On the other hand, every continuous function f: [0,1] → R achieves its maximum and minimum values, where [0,1] denotes the closed interval.

ah ok, i see.

sin(x/2) = cos(x/2)

x = 4 (pi n-tan^(-1)(1-sqrt(2))), n element Z
x = 4 (pi n-tan^(-1)(1+sqrt(2))), n element Z

http://www.wolframalpha.com/input/?i=si ... 28x%2F2%29

Hmm looks like more pure mathematics than what I do in the more engineering related maths....Interesting thread though, keen to see what pops up

The equation bx^2+2bx=8 has one sollution, find b. i might be stupid, but i need help

well... if it has one solution that means that the + and - versions of the quadratic formula equal each other.... so use that, plug it in for x, and solve for b.

which means that inside the root of the abc formula you will get 0, right?

yesh