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Let y=f(x)y = f(x) be the solution curve of the differential equation dydx+2y2=0\dfrac{dy}{dx} + 2y^2 = 0 if f(1)=1f(1) = 1, then f(2)f(2) is equal to

Solution

✅ Correct Option: 3

Separating, dy/y2=−2 dxdy/y^2 = -2\,dx, so −1/y=−2x+c-1/y = -2x + c, i.e. 1/y=2x+c11/y = 2x + c_1.

Using f(1)=1f(1)=1 gives 1=2+c11 = 2 + c_1, so c1=−1c_1 = -1 and 1/y=2x−11/y = 2x-1.

At x=2x=2, f(2)=1/3f(2) = 1/3.

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