Q.The order and degree of the differential equation d dx(ey) = 0 respectively are 1
(A) 0, 1
(B) 1, 1
(C) 2, 1
(D) 1, not defined
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Start your 14-day free trial to unlock the full solution →The given equation simplifies to , which is a first-order differential equation. Since , the highest derivative is raised to the power 1, so the degree is 1. The correct option is (B).
The order of a differential equation is the highest order derivative present. The degree is the power of the highest order derivative, provided the equation is polynomial in derivatives. Here, the equation looks deceptively simple — but we must first expand it properly.
- Expand the derivative. The given equation is . Using the chain rule:
So the equation becomes:
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Identify the highest derivative.
The only derivative present is , which is a first derivative. Hence the order is .
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Determine the degree.
The degree is defined only when the differential equation is a polynomial in the derivatives. Here, the term is not a polynomial in or its derivatives — it's an exponential function of . However, the derivative itself appears with power 1, and the equation is already in the form .
Since is never zero for any real , we can divide both sides by to get:
This is a polynomial in (specifically, it is ). So the degree is . …
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