sin50(1+√3tan10) =2sin50[(1/2)+[ (√3/2)(sin10/cos10)] =2sin50[sin30+cos30(sin10/cos10)] =2sin50/cos10[sin30cos10+cos30sin10] =2sin50/cos10*sin40 =(2cos40sin40)/cos10 =sin80/cos10 =cos10/cos10 =1
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