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in Sets, relations and functions by (476 points)
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f: [-2, 2]  R,

f(x)-min(-√1-(x-1)2,√1-(x-1)2|x|), then the number of points where function f is non-differentiable, is

image

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1 Answer

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Since, for domain of \(\sqrt{1-(x+1)^2},\) we have

1 - (x + 1)2 \(\geq\) 0

⇒ (x + 1)2 \(\leq\) 1

⇒ -1 \(\leq\) x + 1 \(\leq\) 1

⇒ -2 \(\leq\) x \(\leq\) 0

For domain of \(\sqrt{1-(x-1)^2},\) we have

1 - (x - 1)2 \(\geq\) 0

⇒ (x - 1)2 \(\leq\) 1

⇒ -1 \(\leq\) x - 1 \(\leq\) 1

⇒ 0 \(\leq\) x \(\leq\) 2

Case I: If x \(\in\) [-2, 0] then \(\sqrt{1-(x-1)^2},\) is not defined and

\(-\sqrt{1-(x+1)^2}\leq0\)

but |x| \(\geq\) 0

\(\therefore\) Min {\(-\sqrt{1-(x+1)^2},\) \(\sqrt{1-(x-1)^2}\), |x|} = \(-\sqrt{1-(x+1)^2}\) if x \(\in\) [-2, 0]

Case II: If x \(\in\) [0, 1] then \(-\sqrt{1-(x+1)^2}\) is not defined 

And |x| \(\leq\) \(\sqrt{1-(x-1)^2}\)

 \(\therefore\) Min {\(-\sqrt{1-(x+1)^2},\) \(\sqrt{1-(x-1)^2}\), |x|} = |x| if x \(\in\) [0, 1]

Case III: If x \(\in\) [1, 2] then \(-\sqrt{1-(x+1)^2}\) is not defined 

and |x| \(\geq\) \(\sqrt{1-(x-1)^2}\) (\(\because\) Maximum value of \(\sqrt{1-(x-1)^2}\) is 1)

\(\therefore\) Min {\(-\sqrt{1-(x+1)^2}\), \(\sqrt{1-(x-1)^2}\), |x|} = \(\sqrt{1-(x-1)^2}\) , if x \(\in\)[1, 2]

\(\therefore\) f(x) = \(\begin{cases}-\sqrt{1-(x+1)^2}&;x\in[-2,0]\\|x|&;x\in[0,1]\\ \sqrt{1-(x-1)^2}&x\in[1,2]\end{cases}\)

and its graph is

Total number of non-differentials points is 2 which is x = 0, x = 1

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