Tan x=4/3. Write down possible value of cos x.?
回答 (7)
2017-06-21 1:58 am
✔ 最佳答案
3,4,5 right triangle4/3 = (4/5) / (3/5)
top is sine, bottom cosine, since tan = sin/cos
so answer is 3/5 if x is in QI and -3/5 if x is in QIII
2017-06-21 1:51 am
±3/5
2017-06-21 2:23 am
cos x = 3 / 5
2017-06-21 1:51 am
cos(x) = ±√1/(tan(x)^2 +1) = ±√(1/(16/9 +1)
.. = ±√(9/25)
cos(x) = ±3/5
.. = ±√(9/25)
cos(x) = ±3/5
2017-06-21 1:28 am
±⅗
(cosθ,sinθ) = (⅗,⅘), (-⅗,-⅘)
(cosθ,sinθ) = (⅗,⅘), (-⅗,-⅘)
2017-06-21 1:26 am
Tan x = Sin x / Cos x = 4/3
Since Sin^2 x + Cos^2 x = 1, you can use that to find that Sin x = +/- 4/5 and the Cos x = +/- 3/5
Since Sin^2 x + Cos^2 x = 1, you can use that to find that Sin x = +/- 4/5 and the Cos x = +/- 3/5
2017-06-21 1:26 am
± 3 / 5
收錄日期: 2021-04-24 00:30:18
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