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(1+cotα-cscα)(1+tanα+secα)

题目详情
(1+cotα-cscα)(1+tanα+secα)
▼优质解答
答案和解析
(1+cot a-csc a )*(1+tan a+sec a )
=(sin a/sin a+cos a/sin a-1/sin a)*(cos a/cos a+sin a/cos a+1/cos a)
=(sin a+cos a-1)/sin a*(cos a+sin a-1)/cos a
=[(sin a+cos a)^2-1]/(sin a*cos a)
=[sin a^2+2sin a*cos a+cos a^2-1]/(sin a*cos a)
=[2sin a*cos a+1-1]/(sin a*cos a)
=(2sin a*cos a)/(sin a*cos a)
=2