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b)

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The function is 2x7 + 7x4+ 2 = 0

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Let  f(x) = 2x7 + 7x4+ 2

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Given x1 = 1

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Find x2 = ?  and  x3 = ?

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f \\'(x) = 2*7x7-1 + 7*4x4-1

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f \\'(x) = 14x6 + 28x3

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According to Newton Method  \"image\"

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x2 = x1 – [ f(x1) / f’(x1) ]

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f(x1) = 2(x1)7 + 7(x1)4+ 2

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f(x1) = 2(1)7 + 7(1)4+ 2 =  2 + 7 + 2 = 11

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f \\'(x1) = 14(x1)6 + 28(x1)3 = 14(1)6 + 28(1)3 = 14 + 28 = 42

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x2 = x1 – [ f(x1) / f’(x1) ]

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x2 = 1 – [ 11 / 42 ]

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x2 = 1 – 0.2619

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x2 = 0.738

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x3 = x2 – [ f(x2) / f’(x2) ]

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f(x2) = 2(x2)7 + 7(x2)4+ 2

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f(x2) = 2(0.738)7 + 7(0.738)4+ 2

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=  0.238 + 2.076 + 2

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= 4.314

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f \\'(x2) = 14(x2)6 + 28(x21)3

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= 14(0.738)6 + 28(0.738)3

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= 2.26 + 11.25

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= 13.51

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x3 = x3 – [ f(x3) / f’(x2) ]

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x3 = 1 – [ 4.314 / 13.51 ]

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x3 = 1 – 0.319

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x3 = 0.681

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Solution :

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x3 = 0.681

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