Rewrite the expression as an algebraic expression in x.
1). sin [ arctan(11x)]
2).sin [ 2 arcsin (9x)]
Thanks!
Trigonometry
2011-09-14 8:09 pm
回答 (1)
2011-09-14 9:04 pm
✔ 最佳答案
1).Let u = arctan 11x
Then tan u = 11x
sin u
= ±tan u /√(1 + tan²u)
= ±11x / √(1 + 121x²)
sin (arctan 11x)
= sin u
= ±11x / √(1 + 121x²)
2).
Let u = arcsin 9x
Then 9x = sin u
cos u
= ±√(1 - sin²u)
= ±√(1 - 81x²)
sin (2arcsin 9x)
= sin 2u
= 2 sin u cos u
= 2 * 9x * [±√(1 - 81x²)]
= ±18x√(1- 81x²)
參考: Tsui
收錄日期: 2021-04-13 18:14:35
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