Question

Find the general solution of 2cos2x=0​

Answer 1

cos2xcscx−2cos2x=0

cos2x(cscx−2)=0

x=π 3(6k±1),k∈Z

1 cosx=2⇒cosx=1 2⇒x=±π 3+2kπ =π 3(6k±1),

∴x=π 4(2k±1)

cos2x=0⇒2x=±π 2+kπ⇒x =π 4(2k±1),k∈Z

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