For the equation y″ + 5y′ + 6y = 0, find the root r of the characteristic equation that is closest to zero. It sets how slowly the solution dies out.
Differential equations worksheet with answers
1.Easy
y″ + 5y′ + 6y = 0
r =
2.Easy
For the equation y″ + 9y′ + 18y = 0, find the root r of the characteristic equation that is closest to zero. It sets how slowly the solution dies out.
y″ + 9y′ + 18y = 0
r =
3.Medium
Solve y″ + 8y′ + 16y = 0 with y(0) = 2 and y′(0) = 1. Find y(0.5).
y″ + 8y′ + 16y = 0y(0) = 2y′(0) = 1
y(0.5) =
4.Medium
Solve y″ + 4y′ + 4y = 0 with y(0) = 3 and y′(0) = 0. Find y(1.5).
y″ + 4y′ + 4y = 0y(0) = 3y′(0) = 0
y(1.5) =
5.Hard
Solve the initial value problem y′ + 3y/x = 6x2 for x > 0, with y(1) = 4. Find y(3).
y′ + 3y/x = 6x2y(1) = 4
y(3) =
6.Hard
A tank holds 100 L of pure water. Brine with 0.05 kg of salt per litre flows in at 20 L/min, and the well-mixed solution flows out at the same rate. After how many minutes t does the tank contain 3 kg of salt?
V = 100 Lm0 = 0 kgc = 0.05 kg/Lr = 20 L/min
t = min
Answer key
- 1. r = −2
- 2. r = −3
- 3. y(0.5) = 0.8797
- 4. y(1.5) = 0.5974
- 5. y(3) = 27.11
- 6. t = 4.581 min
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