The GATE Grind

GATE 2024 AG – Question 37

Engineering Mathematics · Differential Equations · 2 marks · Multiple choice

Solve $y^{\prime\prime}+2y^{\prime}-3y=0$ with $y(0)=0,y^{\prime}(0)=8$.

  1. $2(e^x-e^{3x})$
  2. $2(e^x-e^{-3x})$
  3. $2(e^x+e^{3x})$
  4. $2(e^x+e^{-3x})$

Practise this question in The GATE Grind →

Show answer and explanation

Correct answer: (B) $2(e^x-e^{-3x})$

Explanation

The characteristic equation $(r-1)(r+3)=0$ gives $y=Ae^x+Be^{-3x}$. At0,$A+B=0$ and $A-3B=8$. Thus A=2,B=−2,and $y=2(e^x-e^{-3x})$,**B**. Its initial derivative is 2+6=8.

More Differential Equations questions

All Differential Equations questions →