The difference of the order and degree of the differential equation $\left(\frac{d^2 y}{d…

The difference of the order and degree of the differential equation $\left(\frac{d^2 y}{d x^2}\right)^{-\frac{7}{2}}\left(\frac{d^3 y}{d x^3}\right)^2-\left(\frac{d^2 y}{d x^2}\right)^{-\frac{5}{2}}\left(\frac{d^4 y}{d x^4}\right)=0$ is
  1. 5
  2. 3
  3. 4
  4. 2

Solution

Given differential equation $\begin{aligned} & \left(\frac{d^2 y}{d x^2}\right)^{-\frac{7}{2}} \cdot\left(\frac{d^3 y}{d x^3}\right)^2-\left(\frac{d^2 y}{d x^2}\right)^{-\frac{5}{2}} \cdot\left(\frac{d^4 y}{d x^4}\right)=0 \\ & \Rightarrow\left(\frac{d^2 y}{d x^2}\right)^{-7} \cdot\left(\frac{d^3 y}{d x^3}\right)^4-\left(\frac{d^2 y}{d x^2}\right)^{-5} \cdot\left(\frac{d^4 y}{d x^4}\right)^2=0 \\ & \Rightarrow\left(\frac{d^3 y}{d x^3}\right)^4 \cdot\left(\frac{d^2 y}{d x^2}\right)^5-\left(\frac{d^2 y}{d x^2}\right)^7 \cdot\left(\frac{d^4 y}{d x^4}\right)^2=0 \end{aligned}$ So, order $=4$, degree $=2$ Now, order - degree $=4-2=2$.

Asked in: AP EAMCET 2024 (19 May Shift 2)

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