sincos

👨🏻‍🏫 學術台數學

用戶128691

2007-04-16 7:28 am

if θ is smaller or　equal to 360 but larger or eaual to 0, solve (cosθ-3)(3sinθ-2)=0 correct to 3 sig. fig.

更新1:

ANSWER 點解係0.730 or 2.41??????????????????

更新2:

ANSWER 點解係0.730 or 2.41??????????????????

回答 (2)

風鈴鈴

2007-04-16 5:44 pm

✔ 最佳答案

0≦θ≦2丌
(cosθ - 3)(3sinθ - 2) = 0
cosθ = 3 (rejected, -1≦cosθ≦1)
or sinθ = 2/3
θ = 0.730 or θ = 2.41 (cor. to 3 sig. fig.)

2007-04-16 09:47:34 補充：
題目問得唔清楚，因為你話θ is smaller or equal to 360(°?) but larger or equal to 0即係0°≦θ≦360°，係Degree做單位既不過你個答案係Radian做單位，所以請你將上面個位既答案乘(丌/180°)就係你要既答案

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LeonaCHoco

2007-04-16 7:35 am

(cosθ-3)(3sinθ-2)=0

cosθ-3=0 or 3sinθ-2=0

cosθ=3(rejected) or sinθ=2/3

sinθ=2/3

θ=41.810 or 138.190

2007-04-16 19:09:47 補充：
--------------------如果是因為我沒有加上˚此符號而令你誤解,就係唔好思意.θ=41.810˚<即0.730> or 138.190˚<即2.412>

2007-04-17 00:24:14 補充：
打漏咗,應該係就真係唔好思意.

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