8j) Solve the equations for 0<y<360
sin 2y - 1 = cos 2y
*show workings
Maths唔識抵死題(160902)
2010-09-17 3:38 am
回答 (1)
2010-09-17 3:46 am
✔ 最佳答案
8j) Solve the equations for 0<y<360sin2y - 1 = cos2y
2sinycosy - 1 = cos^2 y - sin^2 y
2sinycosy = 2cos^2 y
For cos y = 0, y = 90deg or 270deg
For cos y =/=0,
2cos y = 2 sin y
tan y = 1
y = 45deg or (180 + 45)deg = 225deg
y = 45deg or 90deg or 225deg or 260deg
2010-09-16 19:47:12 補充：
y = 45deg or 90deg or 225deg or 270deg,
參考: Hope the solution can help you^^”
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