若cosx^2+sin2x-3sinx^2=1,则tanx已知sinα+3cosα=0,则2sinα^2+2-3sinαcosα的值为设g(x)=asin(πx+a)+bcos(πx+β)+4(字母均为非零常数),若g(2009)=6,则g(2010)=

问题描述:

若cosx^2+sin2x-3sinx^2=1,则tanx
已知sinα+3cosα=0,则2sinα^2+2-3sinαcosα的值为
设g(x)=asin(πx+a)+bcos(πx+β)+4(字母均为非零常数),若g(2009)=6,则g(2010)=

sinα+3cosα=0
sinα=-3cosα
tanα=-3
2sinα^2+2-3sinαcosα
=2sinα^2+2+sinα^2
=3sinα^2+2
=3sinα^2/1+2
=3sinα^2/(sinα^2+cosα^2)+2
=3tanα^2/(tanα^2+1)+2
=27/10+2
=47/10
g(x)= asin(πx+α)+bcos(πx+β)+4
设f(x)= g(x)-4= asin(πx+α)+bcos(πx+β)
则有f(x)= asin(πx+α)+bcos(πx+β)
则有f(x+1)=asin[π(x+1)+α]+bcos[π(x+1)+β]
= -[asin(πx+α)+bcos(πx+β)]
=-f(x)
f(x+1)=-f(x)
f(2009)=g(2009)-4=6-4=2
-f(2009)=f(2009+1)=f(2010)=g(2010)-4=-2
g(2010)=2