Question 1 [15 marks]
a) Derive the Newton’s iterative formula for finding the fourth root of positive number A, i.e. ∑A.
b) Use the iterative formula obtained in (a) to compute ∑270 correct to three decimal places.
c) Approximate using secant method the positive root of the function
f(x) = x − 0.2 sin x − 0.5,
Perform three iterations and truncate your answer to three significant digits.
Question 2 [15 marks]
a)
Consider the following function
f(x) = e^2x cos 3x
Let 0 ≤ x < 0.6
i) Construct a second-degree Lagrange interpolating polynomial for f(x), where the step size h = 0.3. Leave the polynomial in simplest form.
ii) Find the bound for absolute error on the interval [x0, xn].
b)
Find the percentage relative error in y at x = 1, if the error in x is 0.04, and
y = 4x^6 − 5x