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NDA 2023 Maths · Mathematics · Differential Equations · easy

Y=e^2x satisfies the equation (d^2y)/(dx^2-4y=0. 2. y=sin x satisfies the equation (d^2y)/(dx^2+y=0.

Single correct option

Consider the following statements:
1. y=e2xy=e^{2x} satisfies the equation d2ydx2−4y=0\dfrac{d^2y}{dx^2}-4y=0.
2. y=sin⁡xy=\sin x satisfies the equation d2ydx2+y=0\dfrac{d^2y}{dx^2}+y=0.
Which of the statements given above is/are correct?
  1. A. 1 only
  2. B. 2 only
  3. C. Both 1 and 2
  4. D. Neither 1 nor 2
Show answer and solution

Answer: (C) Both 1 and 2

For y=e2xy=e^{2x}, y′′=4e2x=4yy''=4e^{2x}=4y, so y′′−4y=0y''-4y=0 and Statement 1 is true. For y=sin⁡xy=\sin x, y′′=−sin⁡xy''=-\sin x, so y′′+y=0y''+y=0 and Statement 2 is true. Both functions satisfy their respective equations.
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