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vanhuyen12h1
![](https://blog.hocmai.vn/wp-content/uploads/2017/07/hot.gif)
![](https://blog.hocmai.vn/wp-content/uploads/2017/07/hot.gif)
trong mot mach dao dong LC,dien tich tren ban tu bien thien theo phuong trinh q=Qcos(wt-bi/2)thi
A:tai thoi diem T/4 va 3T/4 ,dong dien trong mach co do lon max,co chieu nhu nhau
A:tai thoi diem T/4 va 3T/4 ,dong dien trong mach co do lon max,co chieu nhu nhau