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问题: 三角函数化简的题目

(sinx+cosx-1)(sinx-cosx+1)
------------------------------
sin2x


帮忙化个简

还有过程哦

解答:

(sinx+cosx-1)(sinx-cosx+1)
=--------------------------
sin2x

[sinx+(cosx-1)][sinx-(cosx-1)]
=--------------------------------
sin2x

sin^x-(cosx-1)^
=---------------
sin2x

sin^x-cos^x+2cosx-1
=--------------------
sin2x

-2cos^x+2cosx
=---------------
sin2x

2cosx(1-cosx)
=---------------
2sinxcosx

1-cosx
=--------
sinx

2sin^(x/2)
=------------------
2sin(x/2)cos(x/2)

sin(x/2)
=------------
cos(x/2)

=tan(x/2)