H
hiep221993
cau I, minh se ko lam vi cau nay de~
cauII,
1, 2cos^2.sinx -2cos^2(x/2) +sin2x = 0
Nhom no vao de ban oi
<=> sin2x(cosx +1) – (cosx + 1) = 0 ( cos^2(x/2) = cosx +1 theo cong thuc ha bac.
(cosx + 1)(sin2x – 1) = 0
Giai den day thui
2>log_2〖2x= 〗 log_2〖2+log_2〖2=log_2〖x+1〗 〗 〗
3^log_2〖x+1〗 =9^log_2x
dat 9^log_2x =t
The la xong tu giai tip nhe
cauII,
1, 2cos^2.sinx -2cos^2(x/2) +sin2x = 0
Nhom no vao de ban oi
<=> sin2x(cosx +1) – (cosx + 1) = 0 ( cos^2(x/2) = cosx +1 theo cong thuc ha bac.
(cosx + 1)(sin2x – 1) = 0
Giai den day thui
2>log_2〖2x= 〗 log_2〖2+log_2〖2=log_2〖x+1〗 〗 〗
3^log_2〖x+1〗 =9^log_2x
dat 9^log_2x =t
The la xong tu giai tip nhe