IF cos(-θ)=(3/5) and sinθ <0, find tan θ?
回答 (4)
2016-07-20 8:00 pm
✔ 最佳答案
tan Ө = - 4 / 3
2016-07-20 8:32 pm
cos(-θ) = (3/5)
cos(θ) = (3/5)
sin²(θ) + cos²(θ) = 1
sin²(θ) + (3/5)² = 1
sin²(θ) + (9/25) = 1
sin²(θ) = 1 - (9/25)
sin²(θ) = 16/25
Since sin(θ) < 0, then sin(θ) = -√(16/25)
Hence, sin(θ) = -4/5
cos(θ) = (3/5)
sin²(θ) + cos²(θ) = 1
sin²(θ) + (3/5)² = 1
sin²(θ) + (9/25) = 1
sin²(θ) = 1 - (9/25)
sin²(θ) = 16/25
Since sin(θ) < 0, then sin(θ) = -√(16/25)
Hence, sin(θ) = -4/5
2016-07-20 8:15 pm
cos t = 3/5
sin t = +/-4/5
tan t = 4/3
sin t = +/-4/5
tan t = 4/3
2016-07-20 7:58 pm
Hi
收錄日期: 2021-04-18 15:20:16
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20160720115846AAdbGH8