(2)升幂公式:1+cos\alpha =2cos^2\frac{\alpha }{2},1-cos\alpha =2sin^2\frac{\alpha }{2}。综上所述,本题答案为(1)\frac{1-cos2\alpha }{2};\frac{1+cos2\alpha }{2},(2)2cos^2\frac{\alpha }{2};2sin^2\frac{\alpha }{2}。
解析 D ∵2sin2\alpha =1-cos2\alpha ,∴4sin\alpha cos\alpha =2sin^2\alpha ∴tan\alpha =2又sin^2\alpha +cos^2\alpha =1 ,\alpha \in (0,\dfrac{π}{2} )∴sin\alpha =\dfrac {2\sqrt {5}}{5}综上所述,本题答案为D。
Step by step video & image solution for If 2sinalpha/(1+cosalpha+sinalpha)=y then value of (1-cosalpha+sinalpha)/(1+sinalpha) is by Maths experts to help you in doubts & scoring excellent marks in Class 12 exams.Updated on:21/07/2023 ...
sin^2α +cos^2α =1的变形公式:$sin^2\alpha =1-cos^2\alpha =(1+cos\alpha )(1-cos\alpha )⟹ (si
α=πn2+2π, n2∈Z 解α α=22πn1+arcsin(54), n1∈Z α=πn2+2π, n2∈Z 測驗 Trigonometry 2sin2α=cos2α+1 來自Web 搜索的類似問題 If sinα+cosα=0.2, find the numerical value of sin2α. https://math.stackexchange.com/questions/451199/if-sin-alpha-cos-alpha-0-2-find-the...
alpha \in \left(0,\dfrac{\pi }{2}\right),\therefore \cos \alpha =\sqrt{1-\sin ^{2}\alpha }=\dfrac{3\sqrt{10}}{10}$,$\tan \alpha =\dfrac{1}{3}$,$\therefore \tan 2\alpha =\dfrac{2\tan \alpha }{1-\tan ^{2}\alpha }=\dfrac{3}{4}$,$\therefore \tan \left...
frac { 2 \tan \alpha } { 1 - \tan ^ { 2 } \alpha } = \frac { 2 \times 2 } { 1 - 2 ^ { 2 } } = - \frac { 4 } { 3 }\$ \$\frac { 2 \cos ^ { 2 } \alpha } { 2 \sin \alpha \cos \alpha } = \frac { 1 } { 2 }\$ \$- \frac { 4 ...
\$\sin 2 \alpha \cos \alpha = 2 \sin \alpha \left( 1 - \sin ^ { 2 } \alpha \right)\$ 证明:. 相关知识点: 试题来源: 解析 证明: 证明: \$\sin 2 \alpha \cos \alpha = 2 \sin \alpha \cos \alpha \cos \alpha\$ \$= 2 \sin \alpha \cdot \cos ^ { 2 } \...
解:∵ \dfrac {1+\cos 2α}{\sin 2\alpha }= \dfrac {1}{2},可得: \dfrac {2\cos ^{2}α}{2\sin \alpha \cos \alpha }= \dfrac {\cos α}{\sin \alpha }= \dfrac {1}{\tan \alpha }= \dfrac {1}{2},∴解得:\tan α=2.故选:A.由条件利用同角三角函数的基本关系,...
百度试题 结果1 题目\$\frac { \sin \alpha } { 1 - \cos 2 \alpha } = \tan \alpha\$ .() 相关知识点: 试题来源: 解析 5.提示: _ 反馈 收藏