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GATE 2021 MT – Question 47

Engineering Mathematics · Numerical methods · 2 marks · Numerical answer

Use Newton–Raphson on $f(x)=x-\cos x$ with initial guess 0.5 radians. The root estimate after one iteration is ______ (three decimal places).

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Correct answer: 0.745 to 0.770

Explanation

For f=x−cosx, f′=1+sinx.

Thus x1=0.5−(0.5−cos0.5)/(1+sin0.5)=0.755222. To three decimals, **0.755**.