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Engineering Mathematics Miscellaneous

Engineering Mathematics

  1. Given the ordinary differential equation
    d2y
    +
    dy
    = 0
    dx2dx

    with(0) = 0 and
    dy
    (0) = 1, the value of y(1) is
    dx

    _______ (correct to two decimal places).
    1. 1.4678
    2. 1.4628
    3. 1.4698
    4. 1.46
Correct Option: A

(D2 + D – 6) y = 0
y (0) = 0,
y' (0) = 1
(D + 3) (D – 2) y = 0
D = 2, – 3
C .F. = C1 e2x + C2 e–3x
y = c1 e2x + C2 e–3x
y (0) = 0
So, 0 = C1 + C2 ----------------------(i)

y = (1) =
e2 - e- 3
= 1.4678
5

y (0) = 1
1 = 2 C1 – 3 C2 ___(ii)
From equations (i) & (ii), we get
C1 =
1
, C2 =
- 1
55

y =
e2x
-
e- 3x
55

when, x = 1
y = (1) =
e2 - e- 3
= 1.4678
5



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