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3/ \[v=\lambda .f=0,8.500=400(m/s)\] DA4/ \[f=\frac{\omega }{2\pi }=\frac{4\pi }{2\pi }=2(hz)\\\lambda =\frac{v}{f}=\frac{1,2}{2}=0,6(m)\]DA:A5/\[u=8cos(10x-80t);\frac{2\pi }{\lambda }=10;\lambda =\frac{2\pi }{10}=\frac{\pi }{5}\\f=\frac{\omega }{2\pi }=\frac{80}{2\pi }=\frac{40}{\pi };v=\lambda .f=\frac{\pi }{5}.\frac{40}{\pi }=8(m/s)\] DA:C
3/
\[v=\lambda .f=0,8.500=400(m/s)\]
DA
4/
\[f=\frac{\omega }{2\pi }=\frac{4\pi }{2\pi }=2(hz)\\\lambda =\frac{v}{f}=\frac{1,2}{2}=0,6(m)\]
DA:A
5/
\[u=8cos(10x-80t);\frac{2\pi }{\lambda }=10;\lambda =\frac{2\pi }{10}=\frac{\pi }{5}\\f=\frac{\omega }{2\pi }=\frac{80}{2\pi }=\frac{40}{\pi };v=\lambda .f=\frac{\pi }{5}.\frac{40}{\pi }=8(m/s)\]
DA:C
