The bisection method starts on an interval of length 1. Every step halves the interval. How many steps n are needed at least before the interval is shorter than 0.05?
Numerical methods worksheet with answers
1.Easy
b − a = 1ε = 0.05
n =
2.Easy
Apply Newton–Raphson to f(x) = e−x − x with the starting value x₀ = 0. Find x1.
f(x) = e−x − xf′(x) = −e−x − 1x₀ = 0
x1 =
3.Medium
The trapezoid rule is used for ∫02 sin x dx. The error is at most (b − a)³·M/(12n²) with M = max|f″| on [0, 2]. Find the smallest number of strips n that guarantees an error below 0.001.
f(x) = sin x[a, b] = [0, 2]ε = 0.001
n =
4.Medium
The trapezoid rule is used for ∫12 1/x dx. The error is at most (b − a)³·M/(12n²) with M = max|f″| on [1, 2]. Find the smallest number of strips n that guarantees an error below 0.0005.
f(x) = 1/x[a, b] = [1, 2]ε = 0.0005
n =
5.Hard
Use Heun's method (improved Euler) with h = 0.1 for y′ = 1 + sin(ty), y(0) = 1 to estimate y3 ≈ y(0.3).
y′ = 1 + sin(ty)y(0) = 1h = 0.1
y3 =
6.Hard
Use Heun's method (improved Euler) with h = 0.2 for y′ = e−ty, y(0) = 0.5 to estimate y2 ≈ y(0.4).
y′ = e−tyy(0) = 0.5h = 0.2
y2 =
Answer key
- 1. n = 5
- 2. x1 = 0.5
- 3. n = 26
- 4. n = 19
- 5. y3 = 1.355
- 6. y2 = 0.845
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