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Form a differential equation representing the given family of curves by eliminating arbitrary constant a and b.y = ae3x + be-2x |
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Answer» y = a e3x + b e-2x ….(1) Differentiating w.r.t x , y, = ae3x.3 + be2x (-2) ….(2) multiply (1) by 3 ⇒ 3y = 3ae3x + 3be-2x ⇒ 3ae3x = 3y -3be-2x …(3) put (3) in (2), we get y, = 3y – 3be-2x – 2be-2x ⇒ y – 3y = -5 be-2x …….. (4) differentiating again ⇒ y2 – 3y1 = -5be-2x (-2) ….(5) multiply (4) by 2, we get ⇒ 2y,- 6y = -10be2x ….(6) putting (6) in (5), we get ⇒ -(2y1 – 6y) = y2 -3y1 ⇒ y2 – 3y1 + 2(y1 3y) = 0 ⇒ y2 -y1 – 6y = 0 is the required differential equation. |
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