第十七章

$$ \mathbf{1}\mathbf{7}-\mathbf{1}\quad u=1-8i^{2}+8i^{4} $$

$$ \mathbf{1}7-\mathbf{2}\quad u_{1}^{3}+(u_{1}-u_{2})^{2}=12,u_{2}^{\frac{3}{2}}-(u_{1}-u_{2})^{2}=4 $$

$$ 17-3\quad3\mathrm{~J~} $$

$$ 17-4\quad L=4\mathrm{~H~} $$

$$ \mathbf{1}\mathbf{7}-\mathbf{5}\quad i_{1}^{(1)}=0.041\mathrm{~93~A},i_{3}^{(1)}=0.041\mathrm{~92~A} $$

$$ \mathbf{1}7-\mathbf{9}\quad U_{\mathrm{Q}}=0.34\mathrm{~V},I_{\mathrm{Q}}=0.66\mathrm{~A} $$

$$ \mathbf{1}7-\mathbf{1}\mathbf{0}\quad\left[1+\frac{1}{7}\mathrm{c o s}(\omega t)\right]\mathrm{A} $$

$$ \mathbf{1}7-\mathbf{1}\mathbf{1}\quad\left(3-\frac{1}{9}\cos t\right)\mathrm{A} $$

$$ \mathbf{17-12}\quad(1)~U_{\mathrm{q}}\approx1.9\mathrm{~V},I_{\mathrm{q}}\approx1.7\mathrm{~A};(2)~U_{\mathrm{q}}\approx2\mathrm{~V},I_{\mathrm{q}}\approx1.5\mathrm{~A} $$

$$ \begin{array}{r l r}&{17-13}&{R_{\mathrm{d}}=0.5~\Omega}\end{array} $$

$$ \mathbf{17-14}\quad u_{C}=\left(U_{0}^{\frac{2}{3}}-\frac{2}{3}\frac{t}{C}\right)^{\frac{3}{2}}\mathrm{V} $$

$$ \mathbf{17-15}\quad u_{C}(t)=\left(1+2\mathrm{e}^{-t}\right)\mathrm{V},0\leqslant t\leqslant0.693\mathrm{s};u_{C}(t)=\left(3-\mathrm{e}^{t-0.693}\right)\mathrm{V}, $$

$$ 0.693\mathrm{~s}\leqslant t\leqslant1.386\mathrm{~s};u_{C}(t)=\mathrm{e}^{-2(t-1.386)}\mathrm{~V},t>1.386\mathrm{~s} $$