8.2.1.2 Differential equations

Problem: Integrate the following linear differential equation, the right side of which is presented in the graph, shown in the figure. \[ \begin{array}{l} \text { When } \quad t=0, x=0, x^{\prime}=0, \\ x^{\prime \prime}+x=f(t) . \end{array} \] clip2net.com