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The limit $\>\lim_{\Delta x\to0}{\frac {\sqrt{2 + \Delta x}- \sqrt{2}} {\Delta x}}\>$ represents $\>f'(a)\>$ for some function $\>f\>$ and some some number $\>a$ .

a) Find $\>f$ :

b) Find $\>a$ :

You can earn partial credit on this problem.