若α ,β为锐角,P=log以cosα为底(sin50°+sin40°)的对数,
Q=log以cosα 为底(cos25 °+cos65°)的对数,R=log以cosα 为底(sin55°+cos55°)的对数,则P、Q、R的关系是
人气:435 ℃ 时间:2020-05-22 03:37:05
解答
首先发现对数里面的一点小规律:P:sin50°+sin40°=sin40°+cos40°Q:cos25°+cos65°=cos25°+sin25°R:sin55°+cos55°=cos45°+sin45°设f(x)=sinx+cosx=√2(sin(x+45°)),因此当x为锐角时,sin(x+45°)单调减....
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