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If the solution curve of the differential equation (2x - 10y^3) dy + ydx = 0, passes through the points (0, 1) and (2, b), then b is a root of the equation:

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If the solution curve of the differential equation (2x - 10y3) dy + ydx = 0, passes through the points (0, 1) and (2, b), then b is a root of the equation:

(1) y5 – 2y – 2 = 0

(2) 2y5 – 2y – 1 = 0

(3) 2y5 – y2 – 2 = 0

(4) y5 - y2 – 1 = 0

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Correct answer: (4) y5 - y2 – 1 = 0

Explanation:

(2x – 10y3) dy + ydx = 0

⇒ \(\frac{dx}{dy}\) + \((\frac{2}{y})\)x = 10y2

I.F. = \(e^{\int \frac{2}{y}dy}\) = \(e^{2 \ell n(y)}\) = y2

Solution of D.E. is

∴ x.y = ∫(10 y2)y2.dy

xy2 = \(\frac{10y^5}{5}\)+C 

⇒ xy2 = 2y5 + C

It passes through (0, 1) → 0 = 2 + C ⇒ C = - 2

∴ Curve is xy2 = 2y5 - 2

Now, it passes through (2, β)

2 = 2β5 - 2 ⇒ β5 - β2 - 1 = 0

∴ β is root of an equation y5 - y2 – 1 = 0

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