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Ok, they tell me to find a and b so that the function:

f(x)= *Root(2-x^2) if -root(2)<=x<=1

*x^2 + ax + b if x>1

has derivative at 1

I got that the condition for this graph to be continous at 1 is a+b=0

And I moved to check out the derivative stuff:

When x->1+, the derivative is 0

But when 1->1-, igot stuck:

lim (x->1+) of [f(x)-f(1)]/(x-1) = lim (x->1+) of [x^2+ax+b-1]/(x-1)] (from the function at my first post, I got that when x>1, f(x)=x^2+ax+b) How can I figure out the relation between a and b so that I can put it and the one above to an equation?

Help me please, thanks!