计算:
(1)
;
(2)
.
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e38ed99bdbc603028ac0419b455799d.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bbbb5a1dc37a4b3570353729288011b.png)
更新时间:2023-03-13 18:54:02
|
相似题推荐
解答题-问答题
|
适中
(0.65)
名校
【推荐1】塑料袋给我们生活带来了方便,但塑料在自然界可停留长达
年之久,给环境带来了很大的危害,国家发改委、生态环境部等9部门联合印发《关于扎实推进塑料污染治理工作的通知》明确指出,2021年1月1日起,将禁用不可降解的塑料袋、塑料餐具及一次性塑料吸管等.某品牌塑料袋经自然降解后残留量
与时间
年之间的关系为
为初始量,
为光解系数(与光照强度、湿度及氧气浓度有关),
为塑料分子聚态结构系数,已知分子聚态结构系数是光解系数的90倍.(参考数据:
)
(1)塑料自然降解,残留量为初始量的
,大约需要多久?
(2)为了缩短降解时间,该塑料改进工艺,改变了塑料分子聚态结构,其他条件不变,已知2年就可降解初始量的
,则残留量不足初始量的
,至少需要多久?(精确到年)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c10713a24d3ec9dc6991ae016f36de34.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c301ff9f12c61139a78f4522387907b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11bc05f41215f9894e11d1df0465751a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc13a607ac0c7f76d252d7cb1bb040fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e99bcc8b88cf0afe8c151152566a118a.png)
(1)塑料自然降解,残留量为初始量的
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b28555fa2f3a09261cb4e0305d390145.png)
(2)为了缩短降解时间,该塑料改进工艺,改变了塑料分子聚态结构,其他条件不变,已知2年就可降解初始量的
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57f9fd62e62750b30638385031737f89.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b28555fa2f3a09261cb4e0305d390145.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
解题方法
【推荐1】已知
,角
的对边分别为
,向量
,
,且
.
(1)求角
的大小;
(2)若
,
,求
的面积
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24e0c10fb103930eabd5fa18e8f9bb06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0eb9fbb0d0b727f65d6c6d8b0d19bc0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e6369312240b6425c93293cb9989202.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/75facc3fb154fc96f015561c6b32491f.png)
(1)求角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e258ab9e600435b37465092243d99f6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f002f960ec07ea229ed243e2d991d83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐2】已知
的三个内角
所对的三边分别是
,平面向量
,平面向量
,
(1)如果
,
,
的面积
,求
的值;
(2)若
,请判断
的形状.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24e0c10fb103930eabd5fa18e8f9bb06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa5d7c76aeb07c09770296f2b3ddfd5b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/66c41cd8c8c04b868b48c3832973658a.png)
(1)如果
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6de1d395e6c48c0676a1488a299479d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0334bc85843337c4dfcfdc5c638f9f62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a2dd89c37b60b4596ac30e339aa0000.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7cb5138a03b19266f82223899a614f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐3】设函数
,其中向量
,
.
(1)求函数
的最小正周期和在
上的单调递增区间;
(2)当
时,
恒成立,求实数
的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6cc1525aee9019a25cf71dc6054ec1ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/614d46fd0a8a82060c2b2f46e6c91d89.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cebd61b9f0812c826c783100f44e9b9f.png)
(1)求函数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe7d5809da02c15a43a0e9a898b9086.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c195698ac387fe53b3b1e0248a1fcc92.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aee2e5acc7bf0bcd005807758889f8ef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad3aeb26fa9bbf2610637136cda3a057.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
您最近一年使用:0次