(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}。
知识点二 二倍角的正弦、余弦、正切公式$$ \sin 2 \alpha = 2 \sin \alpha \cos \alpha ; $$$ \cos 2 \alpha = \cos ^ { 2 } \alpha - \sin ^ { 2 } \alpha = 2 \cos ^ { 2 } \alpha - 1 = 1 - 2 \sin ^ { 2 } \alpha $$;$$ \tan 2 \alpha = \frac { 2...
यदि tanθ=sinα+cosαsinα+cosα है तो sinα+cosα का मान क्या होगा? View Solution If A=[cosαsinα−sinαcosα], show that A^(2)=[{:(cos2alpha,sin2alpha),(-sin2alpha,cos2alpha) :}]. View Solution (i) यदि...
Hint: 1+tan2α1−tan2α=1+tan4πtan2αtan4π−tan2α=tan(4π−2α) Why is sinα−sinβ=2cos(2α+β)sin(2α−β)? https://www.quora.com/Why-is-sin-alpha-sin-beta-2-cos-left-frac-alpha...
(sin(α)+cos(α))2 Expand sin(2α)+1 Evaluate (sin(α)+cos(α))2 Share Copy Copied to clipboard
知识点二 二倍角公式1.基本公式(1)$$ \sin 2 \alpha = 2 \cos \alpha \cos \alpha $$(2)$$ \cos 2 \alpha = \cos ^ { 2 } \alpha - \sin ^ { 2 } \alpha = 2 \cos ^ { 2 } \alpha - 1 = $$$ 1 - 2 \sin ^ { 2 } \alpha $$(3)$$ \tan 2 \alpha = \frac...
【题目】二倍角公式:$$ \sin 2 \alpha = \_ ; \cos 2 \alpha = \_ = \_ $$___=___;tan 2α=___.
যদি alpha+gamma=2beta হয় তবে দেখাও যে,cotbeta=(sinalpha-singamma)/(cosgamma-cosalpha)
Hint: 1+tan2α1−tan2α=1+tan4πtan2αtan4π−tan2α=tan(4π−2α) Why is sinα−sinβ=2cos(2α+β)sin(2α−β)? https://www.quora.com/Why-is-sin-alpha-sin-beta-2-cos-left-frac-alph...
∴cos^22n+(2cos2α+2)=1 ,即 5cos2o+8cos2a+3=0, 解得 cos2a=-1 或 cos2a=-1/3 , 当cos2o=-1时,sin2o=2cos2o+2=0, sin^2n-sin^2n=(1-cos20)/2+siniα=1 ; 当 cos2α=-3/5 时, sin2α=2cos2α+2=4/5 , sin^2n-sin2n=(1-cos2α)/2+sin2α=5/5 故答案选:...