若tanx=4，求2/3sin^2x+1/4cos^2x的值
答案:1 悬赏:10 手机版
解决时间 2021-11-28 08:27
- 提问者网友：疯子也有疯子的情调
- 2021-11-28 03:22
若tanx=4，求2/3sin^2x+1/4cos^2x的值
最佳答案
- 五星知识达人网友：舍身薄凉客
- 2021-11-28 04:24
(1)
(2/3sin^2x+1/4cos^2x)
=(2/3sin^2x+1/4cos^2x)/1
=(2/3sin^2x+1/4cos^2x)/(sin^2x+cos^2x)
上下同除cos^2x得
=(2/3tan^2x+1/4)/(tan^2x+1)
=(2/3*4+1/4)/5
=7/12
(2)
2sin^2x-sinxcosx+cos^2x
=(2sin^2x-sinxcosx+cos^2x)/1
=(2sin^2x-sinxcosx+cos^2x)/(sin^2x+cos^2x)
上下同除cos^2x得
=(2tan^2x-tanx+1)/(tan^2x+1)
=(2*4-2+1)/5
=7/5
如果你认可我的回答，请点击“采纳为满意答案”,祝学习进步！
(2/3sin^2x+1/4cos^2x)
=(2/3sin^2x+1/4cos^2x)/1
=(2/3sin^2x+1/4cos^2x)/(sin^2x+cos^2x)
上下同除cos^2x得
=(2/3tan^2x+1/4)/(tan^2x+1)
=(2/3*4+1/4)/5
=7/12
(2)
2sin^2x-sinxcosx+cos^2x
=(2sin^2x-sinxcosx+cos^2x)/1
=(2sin^2x-sinxcosx+cos^2x)/(sin^2x+cos^2x)
上下同除cos^2x得
=(2tan^2x-tanx+1)/(tan^2x+1)
=(2*4-2+1)/5
=7/5
如果你认可我的回答，请点击“采纳为满意答案”,祝学习进步！
我要举报
如以上回答内容为低俗、色情、不良、暴力、侵权、涉及违法等信息，可以点下面链接进行举报！
点此我要举报以上问答信息
大家都在看
推荐资讯