角度轉換~~~ - Ans.fyi 參考答案

角度轉換~~~

用戶22880

2007-01-01 11:04 pm

1.. cosec(90度-X)= ?
sec(90度-X) = ?
cot(90度-X) = ?

2..cosec(270度-X)= ?
sec(270度-X) = ?
cot(270度-X) = ?

3..cosec(90度+X)= ?
sec(90度+X) = ?
cot(90度+X) = ?

4..cosec(270度+X)= ?
sec(270度+X) = ?
cot(270度+X) = ?

5. 如果全部變左 (x- 咩度數)，or (x+ 咩度數)，又會點???

回答 (1)

Lau

2007-01-02 9:02 pm

✔ 最佳答案

1)
cot(90-x) = tanx
sec(90-x) = cscx
csc(90-x) = secx

as all functions would have +ve for angle between 0 and 90.

2)
cot(270-x) = tanx
sec(270-x) = -cscx
csc(270-x) = -secx

as cot would have +ve for angle between 180 and 270.

3)
cot(90+x) = -tanx
sec(90+x) = -cscx
csc(90+x) = secx

as csc would have +ve for angle between 90 and 180.

4)
cot(270+x) = -tanx
sec(270+x) = cscx
csc(270+x) = -secx

as csc would have +ve for angle between 270 and 360.

5)
a)
cot(x-90) = -tanx
sec(x-90) = cscx
csc(x-90) = -secx

b)
cot(x-270) = -tanx
sec(x-270) = cscx
csc(x-270) = -secx

the reason is that sec(-x) = secx, but cot(-x) = -cotx and csc(-x) = -cscx for any x.

There is no difference for x+a or a+x for a = 90 or 270.

參考: Myself

👍 0 👎 0