只做第2个
csc40°+cot80=1/sin40`+cos80`/sin80`
=2cos40`/sin80``+cos80`/sin80`
=(2cos40`+cos80`)/sin80`
=(cos40`+cos40`+cos80`)/sin80
=[cos40+cos(60`-20`)+cos(60`+20`)]/sin80`
`=(cos40`+2cos60`c0s20`)/sin80`
=(cos40`+c0s20`)/sin80`
=2cos30`c0s10`/sin80`
=√3cos10`/sin80`=√3
原式=Cos40（2Sin30 Cos10+2Cos30 Sin10）/Cos10
=2Cos40 Sin40/Cos10
=Sin80/Cos10
=1
原式=1/sin40+sin10/cos10
=1/sin40cos10 (cos80+sin10sin40)
=1/sin40cos10 (2sin40cos40+sin10sin40)
=1/cos10 (2sin40+sin10)
夷居然做不出来，哎，最近变笨了。
csc40°+cot80°=cot20° 另一个做不出来,sorry啦
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