1.

Solution of the differential equation 2y sinx.dy/dx  = 2 sin x cos x – y2 cos x satisfying y(π/2) = 1  is(a)   y2 = sin x (b)   y = sin2 x (c)   y2 = cos x +1 (d)   None of these

Answer»

Correct option  (a) y2 = sin x

Explanation:

(2ydy/dx) sinx + y2  cosx = sin 2x

d/dx(y2 sinx) = sin 2x

Integrating both sides,

y2 sin x = -1/2 soc2x + C

Now yπ/2 = 1

1.sinπ/2 = -1/2.(-1) + C

C = 1/2

y2 sin x = 1/2(1 - cos 2x)

y2 sin x = 1/2.2 sin2x

y2 = sin x



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