Recent content by theperthvan

Homework Statement A film director films a scene by photographing it in a plane mirror. The distance from the camera to the actor is 12.0m. The perpendicular distance from the camera to the plane of the mirror is 8.0m. The perpendicular distance from the actor to the plane mirror is also...

I heard of this theory that says if you lean on a wall for a couple of billion years then at some stage you should fall through it. What's this called? Cheers

Thanks mate.

Yeah true, so the definition I had must've been for something with identity=0. So is it really what is sent to the identity?

Just had me algebra exam and that was a question! I pretty much put what HallsofIvy said. I asked the lecturer after and he said that zeroes were to do with the function and roots were an algebraic property. cheers

Nope. Think of x_1 = x ... x_2 = y ... x_3 = z etcetera So yours is just g(x), but for a polynomial g(x_1,x_2)=g(x,y) and could be like x^2-3y-14x^3+37 y^99. Then you switch x and y so give g(y,x)= y^2-3x-14y^3+37 x^99 which is different to g(x,y) so they aren't symmetric.

Thanks. By root I mean (x-3)(x+4)=0 =>x=3,-4. Not square roots or anything. I just remembered something being said like (x-2)^3 has three roots but only 1 x-intercept, and then another question which I can't find seemed to imply it was the same case with zeroes and roots. cheers,

What's the difference between a zero and a root? cheers.

that's really quite elephant, I mean elegant

I think he means something like, for matrices A,B A.B=0 But the problem is is A=[1 1] and B= [-10 0] ...... [0 0] ... [ 10 0] but obviously A=0 or B=0 is not necessarily true. Something like that.

Please will you upload them. cheers

Isn't the kernel the set of stuff that is sent to 0, not the identity?

What about watching a movie? It's kind of like squashing 3D into a flat screen. Like a backwards manifold. Is there some object that describes that?

Just quickly, what is a generator in a group? I have a question: "Give an example of an element in (Z_28,⊕) which is not a generator." Cheers,

of course, thanks