prove this trigonometry, sine theta =cos(90-theta) how this is true with proof?
回答 (6)
2016-11-28 9:50 pm
take right side
cos(90-x)=cos90.cosx+sin90sinx=
=0(cosx0+(1)(sinx)=0+sinx=sinx
cos(90-x)=cos90.cosx+sin90sinx=
=0(cosx0+(1)(sinx)=0+sinx=sinx
2016-11-27 2:48 pm
cos(90 - x) =
cos90cosx + sin90sinx =
0cosx + 1sinx =
sinx
cos90cosx + sin90sinx =
0cosx + 1sinx =
sinx
2016-11-19 9:15 pm
cos(a-b) = cos(a)cos(b) + sin(a)sin(b)
cos(90-theta) = cos(90)cos(theta) + sin(90)sin(theta)
cos(90-theta) = (0) cos(theta) + (1) sin(theta)
= sin(theta)
cos(90-theta) = cos(90)cos(theta) + sin(90)sin(theta)
cos(90-theta) = (0) cos(theta) + (1) sin(theta)
= sin(theta)
2016-11-19 8:42 pm
RTP: sin(t) = cos(90-t). cos(a-b) = cos(a)cos(b) + sin(a)sin(b). Put (a,b) =(90,t). Then cos(90-t) = cos(90)cos(t) + sin(90)sin(t) = 0*cos(t) + 1*sin(t) =
sin(t). QED.
sin(t). QED.
2016-11-19 8:39 pm
cos ( 90 - a )
cos 90 cos a + sin 90 sin a
0 + sin a = sin a
cos 90 cos a + sin 90 sin a
0 + sin a = sin a
2016-11-19 8:31 pm
5 points
收錄日期: 2021-04-23 23:47:49
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