Question

5道数学问题，求解求过程！！！！！！全解100分奖励

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Answer 1

14
sin(π-α)-cos(π+α)
=sinα+cosα
(sinα-cosα)²+(sinα+cosα)²=2
(sinα+cosα)²-(sinα+cosα)²=4sinαcosα
sin³(2π-α)+cos³(2π-α)
=sin³α+cos³α
=(sinα+cosα)(sin²α-sinαcosα+cos²α)
=(sinα+cosα)((sinα-α)²+sinαcosα)
12
cos(-255°-θ)+sin(435°+θ)
=-cos(75°+θ)+sin(75°+θ)
14
sinθ+cosθ=1/5
sin²θ+cos²θ=1
sinθ-cosθ=±√(1-2sinθcosθ)²
13.
原式=(|1-cosα|/|sinα|)+(|1+cosα|/|sinα|)
13.圆内接四边形的对角互补