For the equation y″ + 4y′ + 3y = 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″ + 4y′ + 3y = 0
r =
2.Easy
For the equation y″ + 7y′ + 10y = 0, find the root r of the characteristic equation that is closest to zero. It sets how slowly the solution dies out.
y″ + 7y′ + 10y = 0
r =
3.Medium
Solve y″ + 7y′ + 10y = 0 with y(0) = 3 and y′(0) = -4. Find y(2).
y″ + 7y′ + 10y = 0y(0) = 3y′(0) = -4
y(2) =
4.Medium
A can of soda at 3 °C is taken out of the fridge into a room at 28 °C. After 17 min its temperature is 17 °C. It follows Newton's law of cooling, dT/dt = −k·(T − Tₐ). How long after the start, t, does it take to reach 23 °C?
T0 = 3 °CTa = 28 °CT(17) = 17 °CT = 23 °C
t = min
5.Hard
Solve y′ + 3y = 3e−t with y(0) = 0. Find y(2).
y′ + 3y = 3e−ty(0) = 0
y(2) =
6.Hard
Solve y″ + 3y′ + 18.25y = 0 with y(0) = 10 and y′(0) = 0 (released from rest). Find y(1); angles in radians.
y″ + 3y′ + 18.25y = 0y(0) = 10y′(0) = 0
y(1) =
Answer key
- 1. r = −1
- 2. r = −2
- 3. y(2) = 0.06713
- 4. t = 33.33 min
- 5. y(2) = 0.1993
- 6. y(1) = −2.092
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