Recent content by Lchan1

http://mathforum.org/library/drmath/view/64574.html instead of using euler's formula i multiply by e^-(x/2)/e^-(x/2) after letting z=e^ix I am sorry I was in a rush at school.

Homework Statement I did the question with help, but did not understand why did we multiply e^-i(x/2) How do I know what to multiply for getting the real part of a complex number in exponential form? Homework Equations The Attempt at a Solution

Instead of your approach, I used F=-kx and integrate to get 1/2kx^2 x(t) is given so I have an equation. w=sqrt (k/m) so things actaully worked nicely. and It was only a page of work.

I am not sure how to make a substitution for dx.

Homework Statement Using x(t)= A cos(wt+phi) verify that the total energy is conserved. Homework Equations V(x)= Integral x to x1 F(x)dx The Attempt at a Solution I thought about using the aboved equation but have no idea where to start.

does that mean it's a rotation and a reflection? pi/3 will be the angle?

i think i am ok now... i just didnt understand what the exam wanted... it was a really old exam. prof worded things differently. would you happen to know how to do this as well? https://www.physicsforums.com/showthread.php?t=307122

Yea as this projects v onto r. I think i didnt understand the question correctly. that's why i got the other answer. so they wanted the vector in A that is neartest to vector r which is projecting R onto A. and the projection could be expressed by r1 and r2

should i just project the vector to the matrix? which i will get (1/3,1/3,0,2/3)

I got an answer (2/3,2/3,-1,1/3) does that sound right to you? I project the vector onto the row space. and v-the projection gives me nearest vector.

Homework Statement Given the matrix A= -1/2 root(3)/2 root(3)/2 1/2 determine if the matrix is a rotation about the origin or a reflection about the positive x axis and find the angle between the that the line makes with the x-axis Homework Equations The...

Homework Statement I have a question about an old exam and i have no idea where to start. The question says: Find the vector in the row space A=[1 0 1 1 /new row 0 1 -1 1] 2x4 matrix nearest to the vector (1,1,-1,1) I have absolutely no clue how to start. Homework Equations The...

K = P(product)/ P(reactant) when everything is in gas state.

Ka = ([H3O+][C5H11N])/[C5H11NH+]?

ok. so I did Ka=Kw/Kb Ka = 7.69E-12 = C5H11NH+/[H3O] and [C5H11N] Ka = [H3O] K= [C5H11NH+]/H3O and C5H11N -log k = 11.11