Does the passport of a sponsor of a UK visit visa applicant have to be valid?

a friend of mine is sending me a letter of invitation to support my application for a UK visit visa for a 2 week holiday. after checking, he realized his passport expired in march 2011. can he still use that as a supporting document for his letter of invitation? what if he sends a copy of his passport and his company ID, can that work?

Will a small Alpine V power be enough for my Kicker 12's?

I just bought some 12'' Kicker comps, 4 ohm, 150 watts RMS, 300 peak. I have an Alpine V power MRP-F240 amp laying around that I believe can be bridged to 100 watt RMS at 4 ohm, it is a 4/3/2 channel amp and much smaller than I usually have used in past systems. So my subs are on the way and I would like another opinion if I should start looking for a new amp.... I also have a kenwood 350 watt 2 channel amp, however, I am partial to Alpine. AND i am having a hell of a time finding a ported box locally, would it be worth the trouble of ordering online and assembling a ported box, or just settle for a sealed? btw i listen to rap and hip hop LOUD

For what point on the curve of y=7x^2-3x is the slope of the tangent line -45?

I know how to find the slope when given coords using mtan=lim x-->a f(x)-f(a)/x-a and y-f(a)=mtan(x-a), but i'm not sure how to work it the other way around. Any help?

Which frequency should I tune my sub box to?

i would try 35 but your amp has a subsonic all the way down at 15hz so alot of the frequencies between 35 and 15 are going to be distorted... never liked those alpine amps for that reason.not a fan of those subs either. they are more for sealed enclosures. but hey give it a try and see how it sounds at 35. just make the port at least double recommended size. i know itll be long but itll be good.

Need help with this calculus question.?

False, because f and g could have the same limit (if they intersect at a) or no limit at all, if one or the other has an asymptote at a.

Need help with wiring size for sub and amp?

Just bought a type r and a mrp-m500 will 8 gauge power/ground work, and what size speaker wire should I use? I'm thinking 12 gauge.

I renewed my Illinois plates online and haven't received my sticker, what do!11?

My plates expired today and I've yet to receive the plate sticker I ordered on the 11th of June. It would kind of suck to get a ticket so I'm wondering if presenting my receipt would be a valid defense if I'm pulled over.