在线购彩

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                在线购彩

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                              2020????????????????

                              ????A??????(sin),????(cos)??????(tan),????(cot)???????(sec)?????(csc)????????A?????????????? ????(sin)??????б?????sinA=a/c ????(cos)??????б?????cosA=b/c ????(tan)????????????t

                              2020-05-24

                              2020????????????????????

                              ??????????????? sin +sin =2sin[( + )/2]cos[( - )/2] sin -sin =2cos[( + )/2]sin[( - )/2] cos +cos =2cos[( + )/2]cos[( - )/2] cos -cos =-2sin[( + )/2]sin[( - )/2] ???????????????

                              2020-05-24

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                              ?п???????????????????????????????????????????????????????????ο??? ??? ???? 1 2020???п??????????????????????? ????? 2 2020???п??????????????????????? ?????

                              2019-10-29

                              2020???п???????????????????????

                              sin +sin =2sin[( + )/2]cos[( - )/2] sin -sin =2cos[( + )/2]sin[( - )/2] cos +cos =2cos[( + )/2]cos[( - )/2] cos -cos =-2sin[( + )/2]sin[( - )/2] ?3?????????? ?п?????????? ???????

                              2019-10-06

                              2020???п???????????????????????

                              sin cos =(1/2)[sin( + )+sin( - )] cos sin =(1/2)[sin( + )-sin( - )] cos cos =(1/2)[cos( + )+cos( - )] ?3?????????? ?п?????????? ????????????????????? ???????2020???п???

                              2019-10-06

                              2020???п?????????????????????

                              sin =2tan( /2)/[1+tan^2( /2)] cos =[1-tan^2( /2)]/[1+tan^2( /2)] tan =2tan( /2)/[1-tan^2( /2)] ?3?????????? ?п?????????? ????????????????????? ???????2020???п???

                              2019-10-06

                              2020???п????????????????????

                              sin^2( /2)=(1-cos )/2 cos^2( /2)=(1+cos )/2 tan^2( /2)=(1-cos )/(1+cos ) tan( /2)=sin /(1+cos )=(1-cos )/sin ?3?????????? ?п?????????? ????????????????????? ???????2020

                              2019-10-06

                              2020???п???????????????????????

                              sin3 =3sin -4sin^3( ) cos3 =4cos^3( )-3cos ?3?????????? ?п?????????? ????????????????????? ???????2020???п???

                              2019-10-06

                              2020???п?????????????????????

                              sin(2 )=2sin cos cos(2 )=cos^2( )-sin^2( )=2cos^2( )-1=1-2sin^2( ) tan(2 )=2tan /[1-tan^2( )] ?3?????????? ?п?????????? ????????????????????? ???????2020???п???

                              2019-10-06

                              2020???п????????????????????????

                              cos( + )=cos cos -sin sin cos( - )=cos cos +sin sin sin( )=sin cos cos sin tan( + )=(tan +tan )/(1-tan tan ) tan( - )=(tan -tan )/(1+tan tan ) ?3?????????? ?п?????????? ???

                              2019-10-06

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                              1?????????????????????????a??b??????????б??c?????a2+b2=c2?? 2???????????Rt??ABC?У? C??????? A?????????????( A????? B)?? 3???????????????????????????????????????????????

                              2019-10-06

                              ?п???????????????????????

                              ?п??????????????????????? tan3 =sin3 /cos3 =(sin2 cos +cos2 sin )/(cos2 cos -sin2 sin ) =(2sin cos^2( )+cos^2( )sin -sin^3( ))/(cos^3( )-cos sin^2( )-2sin^2( )cos ) ?????????cos^3( )????? t

                              2019-05-30

                              ?п?????????????????????

                              ?п????????????????????? ?????????????Σ??κ????????????????????????????????????????н??????????????????????a??b??c?????A??B??C???????????? a^2=b^2+c^2-2 b c cosA b^2=a^2+c^2-2 a c c

                              2019-05-30

                              ?п????????????????????????

                              ?п???????????????????????? ??????????? ????????????sin(a+b)=sina*cosb+cosa*sinb??sin(a-b)=sina*cosb-cosa*sinb ??????????????sin(a+b)+sin(a-b)=2sina*cosb ?????sina*cosb=(sin(a+b)

                              2019-05-30

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                              ?п?????????????????????????? ??????????? ??ν??????????????????????n ( /2) ??????????????? ??????????? ??????????? ???????? ????????????????????????????????? sin(2k

                              2019-05-30

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