Toán Lớp 11: giải pt lượng giác sau
sin^2x/2-2cosx/2+2=0
giúp tớ với…cảm ơn trước<3
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Toán Lớp 11: giải pt lượng giác sau
sin^2x/2-2cosx/2+2=0
giúp tớ với…cảm ơn trước<3
Comments ( 1 )
hArr 3 – 2 cos (x/2) – cos (x/2) = 0
hArr – [ cos (x/2) – 1][ cos (x/2) + 3] = 0
hArr [{:( cos (x/2) – 1 = 0),( cos (x/2) + 3 = 0):}:}( k in bbbZ )
hArr [{:( cos (x/2) = 1),( cos (x/2) = – 3):}:}( k in bbbZ )
hArr [{:(x/2 = k 2 pi ),(x/2 = arccos ( – 3) + k 2 pi ),(x/2 = – arccos ( – 3) + k 2 pi ):}:}( k in bbbZ )
hArr [{:( x = k 4 pi ),( x = 2 arccos ( – 3) + k 4 pi ),( x = – 2 arccos ( – 3) + k 4 pi ):}:}( k in bbbZ )