Home » Engineering Mathematics » Engineering Mathematics Miscellaneous » Question

Engineering Mathematics Miscellaneous

Engineering Mathematics

  1. The differential equation
    dy
    + 4y = 5
    dx

    is valid in the domain 0 ≤ x ≤ 1 with y(0) = 2.25. The solution of the differential equation is
    1. y = e4x + 5
    2. y = e–4x + 1.25
    3. y = e–4x + 5
    4. y = e4x + 1.25
Correct Option: B

dy
+ 4y = 5
dx

I.F. = e∫4 dx = e4 x
⇒ y × I.F. = ∫ 5 × (I.F.)dx + C
⇒ y . e4 x = 5.
e4 x
+ C
4

⇒ 2.25 × 1 = 5.
e0
+ C
4

⇒ C = 1
y . e4 x = 5.
e4 x
+ 1
4

⇒ y =
5
+ e-4 x
4

⇒ y = e-4 x + 1.25



Your comments will be displayed only after manual approval.