Question
( left(sec ^{2} yright) frac{d y}{d x}+2 x tan y=x^{3} )
pre ( tan y=t )
( operatorname{sen}^{2} y frac{d y}{d x}=frac{d t}{d x} )
( frac{d t}{d x}+2 x t=x^{3} )
( I f=e^{int e x d x}=e^{x^{2}} )
( frac{4}{t} e^{x^{2}}=int e^{x^{2}} x^{3} d x+c )
Prt ( quad frac{x^{2}}{2 x-1}=t_{1} )
( left(2 x^{2}right) d x=d t_{1} )
y ( t e^{x^{2}}=frac{1}{2} int ln t, d t, quad+c )
( 2 t e^{x^{2}}=t_{1} ln t_{1}-t_{1}+c )
( 2 tan y e^{x^{2}}=e^{x^{2}} x^{2}-e^{x^{2}}+c )
( S )
( z tan y=left(x^{2}-1right)+c e^{-x^{2}} )

Q.15 A solution of differential equation (sec? y) ix + 2x tan y=x ? is (A)2 tan y=c.ex?+x2-1 (B) tan y=ce ** + x2-1 (C) tan y=cen? + x2-1 (D) None of these
Solution
