中三英數問題

2007-03-27 8:05 am

If tan@ = n, by using trigonometric identities, express (4 sin@ + 3 cos @)/(cos @-sin@) in terms of n.

P.S. @ is the angle

回答 (1)

2007-03-27 8:14 am

✔ 最佳答案

(4 sin@ + 3 cos @) / (cos @-sin@)
= (4 sin@/cos@ + 3 cos@/cos@) / (cos@/cos@ - sin@/cos@)
= (4 tan@ + 3) / (1 - tan@)
= (4n + 3) / (1 - n)

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