A bacterial culture starts with 5000 cells and grows according to dN/dt = k·N with k = 0.18 h⁻¹. How many cells N are there after 20 h?
Differential equations worksheet with answers
1.Easy
N0 = 5000k = 0.18 h⁻¹t = 20 h
N =
2.Easy
A bacterial culture starts with 5000 cells and grows according to dN/dt = k·N with k = 0.17 h⁻¹. How many cells N are there after 20 h?
N0 = 5000k = 0.17 h⁻¹t = 20 h
N =
3.Medium
Solve y″ + 8y′ + 15y = 0 with y(0) = 5 and y′(0) = 2. Find y(1).
y″ + 8y′ + 15y = 0y(0) = 5y′(0) = 2
y(1) =
4.Medium
Solve y″ + 2y′ + y = 0 with y(0) = 2 and y′(0) = -1. Find y(0.5).
y″ + 2y′ + y = 0y(0) = 2y′(0) = -1
y(0.5) =
5.Hard
Solve the initial value problem y′ + y/x = 2x for x > 0, with y(1) = 2. Find y(3).
y′ + y/x = 2xy(1) = 2
y(3) =
6.Hard
Solve y′ + 2y = 7e−t with y(0) = 2. Find y(2).
y′ + 2y = 7e−ty(0) = 2
y(2) =
Answer key
- 1. N = 182991
- 2. N = 149821
- 3. y(1) = 0.6149
- 4. y(0.5) = 1.516
- 5. y(3) = 6.444
- 6. y(2) = 0.8558
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