Let f:R→R be a continuous function satisfying
f(x)+∫x0tf(t)dt+x2=0 for all xϵR.Then
f′(x)+xf(x)+2x=0dydx+xy=−2xI.F.=ex22⇒y.ex22=∫ex22(−2x)dx+Cex22.y=−2ex22+Cy=−2+Ceix22f(0)=0⇒C=2f(x)=2⌊e−x22−1⌋