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Solution of differential equation `x^(2)y - x^(3) (dy)/(dx)=y^(4) cos x` isA. `x^(2)y^(-3) = 2 sin x + c`B. `x^(2)y^(-3) = 3 cos x + c`C. `x^(3)y^(-3) = 3 sin x + c`D. `x^(2)y^(3) = 3 sin x + c x^(2) y ` |
Answer» Correct Answer - C `x^(2) y - x^(3)(dy)/(dx)=y^(4)cos x` `(1)/(y^(4))(dy)/(dx)+((-1)/(x))(1)/(y^(3))=(cos x)/(x^(3))` put `(1)/(y^(3))=v` `(1)/(y^(4))(dy)/(dx)=-(1)/(3)(dv)/(dx)` `(-1)/(3)(dv)/(dx)+(-(-1)/(x))v=-(cos x)/(x^(3))` `(dv)/(dx)+(3)/(x)v=3 cos x` `I.F.=e^(3 int (1/2dx)=x^(3)` solution `v*x^(3)=3int cos x dx + c` `(1)/(y^(3))x^(3)=3 sin x + c` `x6(3)y^(-3)=3 sin x + c` |
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