Sarahisme

hey all i am interested in trying to make my own little generator (a hobby type thing). however first i thought that i would look into some of the physics behind it. (i think faraday's law or something is involved) but i have not learnt anything in school yet about doing this kind of thing and was wondering if anyone would like to help me out a little bit with doing or designing this? Cheers Sarah

so let me try again, these are my revised answers.... 1 a) F b) T c) F d) T e) T f) T 2) c please tell me thats right? :S

" columnmatr.jpg " is what i think the basis for the column space of matrix A is...

also if anyone i willing, just quickly, is this right? (for the colmn basis part)

or is because if Ix = Cb then since the Columns of A are linearly independent, then Ax = 0 has only the trivial solution and therefore it is one-to-one, therefore it is a unique solution?

thanks matt

in understand Nicoco way of doing it, but 'uncool' i don't quite get what you mean?

thanks guys yeah proof by contradiction is what i tried at first

this is a vitally important question! any hints?

lol, so which ones did i actually get right? just question 2?

also i have a linear algebra question, if you are willinging to help me a bit with it , that'd be great..... the question is... Suppose A is a 5 × 4 matrix and there exists a 4 × 5 matrix C such that C A = I4 (the 4 × 4 identity matrix). Suppose further that for some given b in R^5, the equation Ax = b has at least one solution. Show that this solution is unique. i started using the inverse matrix theorem, but then realised that was only for square matrices.... any suggestions?

"i need to know whether you're acting on the left or right, ie is this a map from R^3 to R^4, or R^4 to R^3?" i am not sure about that stuff, the question does not explicitely say anything other than what i have posted. so can i just say for the answer to this question that the basis for the null space of matrix A is [0,0,1,0] (meant to be vertical of course )

for the basis for the null space i get: x3[0,0,1,0] (pretend that the stuff between the "[ ]" is actually vertical) so is that right or should there be no x3 there or what?

i've got it now! problem solved

nevermind, i am going crazy....

this is the question, i get a funny answer for the null space bit, the column space part seems ok though... sorry i don't have enough time at the mo to post answers, will do in a few hours when i get some time...

oh ok, yes that makes sense. thanks matt -Sarah

i mean f'(2) is the minimum = -0.9326

which is a minimum value of..... f'(3) = -0.9364

lol, anyone? or am i way off track?

when y = 3?

1) True or false: (a) If the electric field is zero in some region of space, the electric potential must also be zero in that region. (b) If the electric potential is zero in some region of space, the electric field must also be zero in that region. © If the electric potential is zero at a point, the electric field must also be zero at that point. (d) Electric field lines always point toward regions of lower potential. (e) The value of the electric potential can be chosen to be zero at any convenient point. (f) In electrostatics, the surface of a conductor is an equipotential surface. 2) If the voltage across a parallel-plate capacitor is doubled, will its capacitance (a) double, (b) drop by half or © remain the same? My answers would be : 1) a) TRUE b) TRUE c) TRUE d) FALSE e) FALSE f) TRUE 2) (b) how'd i go? Sarah

oops :S, my mistake, g is g(x) = (x+9)^(1/3) - x , and the interval is [2,3]

lighting quick question.... how do you show this? i dunno how to include abs values and stuff.... Thanks Sarah