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in Continuity and Differentiability by (15 points)
Find the value of a,b,c when f(x)= {sin(a+1)x + sinx} / x  when x<0 ; c when x = 0 &  {(x+bx^2)^1/2 - x^1/2} / bx^3/2  when x > 0 ; if x=0 is continuous

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\(f(x)=\frac{sin(a+1)x+sin x}{x},x<0.\)

\(f(x)=c,x=0\)

\(f(x)=\frac{\sqrt{x+bx^2}-\sqrt x}{bx^{3/2}}\;x>0\)

\(f(x) \) is acts at \(x=0.\)

LHL at \(x=0\) is \(f(0^-)=\) \([ \lim_{x\to0} \frac{sin(a+1)(0-h)+sin(0-h)}{0-h}\)

\(\lim_{x\to0} \frac{-sin(a+1)h-sin h}{h}\)

\(=\lim_{x\to0}(a+1)\frac{sin(a+1)h}{(a+1)}+\lim_{x\to0}\frac{sin h}{h}\)

\(=a+1+1(\because \lim_{x\to0} \frac{sin ax}{ax}=1)\)

\(=a+2\)

RHL of \(f(x) \) at \(x=0\) is

\(f(0^+)=​​\lim_{x\to0} \frac{\sqrt{h+bh^2}-\sqrt {h}}{bh^{3/2}}\) ( Replacing \(x\) by \(0+h=h\) )

\(=​​\lim_{h\to0}\frac{h^{1/2}(\sqrt{1+bh}-1)}{bh^{3/2}}\)

\(=​​\lim_{h\to0}\frac{\sqrt{1+bh}-1}{bh}\) \(\frac{0}{0}\) case )

\(=​​\lim_{h\to0}\frac{b}{2\sqrt{1+bh}}\times\frac{1}{b}\) ( By DLH Rule)

\(=​​\lim_{h\to0}\frac{1}{2\sqrt{l+b\times 0}}=\frac{1}{2}\)

\(\because f(x)\) are continuous at \(x= 0\)

 \(\because f(0^-)=f(0^+)=f(0)\) 

\(\because f(0)=C=\frac{1}{2}.\)

\(=a+2=\frac{1}{2}\)

\(\Rightarrow a=\frac{1}{2}-2\)

\(=\frac{-3}{2}.\)

Thus \(a=\frac{-3}{2},b=1\)  and \(C=\frac{1}{2}.\)

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