Use linear interpolation in the table to estimate the value x where y = 1.7945.
Numerical methods worksheet with answers
1.Easy
y = 1.7945
x =
2.Easy
Apply Newton–Raphson to f(x) = ln x + x − 3 with the starting value x₀ = 1. Find x1.
f(x) = ln x + x − 3f′(x) = 1/x + 1x₀ = 1
x1 =
3.Medium
Approximate ∫01.5 sin(x²) dx with the trapezoid rule using n = 4 strips. Give T.
f(x) = sin(x²)[a, b] = [0, 1.5]n = 4
T =
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 0.001.
f(x) = 1/x[a, b] = [1, 2]ε = 0.001
n =
5.Hard
Solve y′ = −0.5y, y(0) = 2 with Euler's method and step h = 0.25 up to t = 1.25. The exact solution is y = y₀e−0.5t. Find the global error |E| = |y(1.25) − y5|.
y′ = −0.5yy(0) = 2h = 0.25
|E| =
6.Hard
Take one step of the classical Runge–Kutta method (RK4) with h = 0.2 for y′ = cos t − y, y(0) = −1. Find y₁ ≈ y(0.2).
y′ = cos t − yy(0) = −1h = 0.2
y1 =
Answer key
- 1. x = 2.225
- 2. x1 = 2
- 3. T = 0.7561
- 4. n = 13
- 5. |E| = 0.0447
- 6. y1 = −0.6387
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