Best U2 Music Videos

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Source:Photo : U2 singer Bono attends a premiere for the film 'U2 3D' at the Palais des Festivals during the 60th International Cannes Film Festival on May 19, 2007 in Cannes, France. (Photo by Francois Durand/Getty Images)

so I understand the derivation for differetiabiity of a function in two variables

but I want to prove if f1 and f2 are conntinuous in a neighborhood (a,b) then f is differentiable at (a,b)

and to understand this proof I need the Mean Value Theorem and what it says but im reall confused at how to get it and what it means exactly –to prove continuity

it says f(a+h,b+k)-f(a,b)=hf1(a+u1h,b+k)+kf2(a,b+u2k)
if f1(x,y) and f2(x,y) are continuous in the neighbohood of the point (a,b) and if the absolute values of h and k are sufficiently small then there exists numbers u1 and u2 such that
f(a+h,b+k)-f(a,b)=hf1(a+u1h,b+k)+kf2(a,b+u2k)

Anyone help Please?

Source:Open Question: PROOFS –Differentiability of a function in 2 variables and MEAN VALUE THEOREM?

 In this edition of the @U2 Podcast:

- Tassoula brings you up to date on U2’s events and releases for December.

- Teresa and Matt crowd around the @U2 roundtable to discuss the "Vertigo 2005 U2 Live from Chicago" DVD.

- Sherry shares her thoughts about hanging around the backstage door to get an autograph in her segment Plot 180.

Enjoy the show!

Source:@U2 podcast, edition 1-6

U2 could be rich… New Statesman, UK - Jun 13, 2008 In case they needed any more money, U2 are set to make up to £6 million next month when they auction a painting by Jean-Michel Basquiat at Sotheby’s. …

Source:U2 could be rich… - New Statesman

I mean something just really incredible & meaningful.

Just to give you an idea, my favorite songs are:

With Or Without You - U2
Nothing Lasts Forever - Maroon 5
Mr. Jones - Counting Crows
Tiny Dancer - Elton John
She Will Be Loved - Maroon 5
100 Years - Five for Fighting
Purple Rain - Prince

Source:Open Question: What is the most amazing song you've ever heard?