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Assuming, $$f(x)=\frac{x^2-9}{x^2+2x-3},\;\;\;\text{if}\;\;x<-3$$ and $$f(x)=a\sin(\pi x)+b,\;\;\;\text{if}\;\; x\geq-3$$ $a$ and $b$ are some constants. find $a$ and $b$ if $f(x)$ is continuous everywhere I use left limit =right limit to compute it I find that $$a\sin(-3\pi)+b =3/2$$ but it is the final ans?? how can I solve $a$ and $b$ also, the question also ask me :are any $a$ and $b$ can make $f(x)$ differentiable everywhere? how can I prove it is correct or incorrext, I have no idea about this.

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    Your approach -- equating limits -- is correct, but there is something missing in your question. Where did $b$ come from?2012-12-10
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    the question said that a and b ar e some constant2012-12-10
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    There is not $b$ in the definition of $f$.2012-12-10
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    sorry i miss it2012-12-10
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    To find $a$ and $b$, evaluate $f$ at some points.2012-12-10
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    Hint: First adjust `b` to make `f` continuous at `-3` (you nearly completed this step, already), then adjust `a` to make `f` differentiable there.2012-12-10
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    so$$ a=-1/2pi$$??2012-12-10

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