Solve y′′=e−xy'' = e^{-x}y′′=e−x.
y=e−x+C1x+C2y = e^{-x} + C_1 x + C_2y=e−x+C1x+C2
y=−e−x+Cy = -e^{-x} + Cy=−e−x+C
y=exy = e^xy=ex
None