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The degree of the differential equation \left[1+\left(\frac{d y}{d x}\right)^{2}\right]^{3 / 2}=\frac{d^{2} y}{d x^{2}}is:
A. 4
B. 3/4
C. not defined
D. 2

 

Answers (1)

Solution

Generally, for a polynomial degree is the highest power.
\left(1+\left(\frac{d y}{d x}\right)^{2}\right)^{\frac{3}{2}}=\frac{d^{2} y}{d x^{2}}
Differential equation is Squaring both the sides,
\Rightarrow\left(1+\left(\frac{d y}{d x}\right)^{2}\right)^{3}=\left(\frac{d^{2} y}{d x^{2}}\right)^{2}
Now for the degree to exit the differential equation must be a polynomial in some differentials.
The given differential equation is polynomial in differential is

\frac{\mathrm{dy}}{\mathrm{dx}} \ and \ \frac{\mathrm{d}^{2} \mathrm{y}}{\mathrm{dx}^{2}}
Degree of differential equation is the highest integer power of the highest order derivative in the equation.
Highest derivative is \frac{d^{2} y}{d x^{2}}
There is only one term of the highest order derivative in the equation which is \left(\frac{d^{2} y}{d x^{2}}\right)^{2}  Whose power is 2 hence the degree is 2.

Option D is correct.

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infoexpert22

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