log4(sin3π/4)+log9[tan(-5 - 知识问答

log4(sin3π/4)+log9[tan(-5π/6)]的值是多少

2个回答

log4(sin3π/4) + log9[tan(-5π/6)]
=log4 (√2/2) + log9 [-tan(5π/6)]
=log4 (√2/2) + log9 [-(-√3/3)]
=log4 (√2/2) + log9 (√3/3)
=log(2^2) [2^(-1/2)] + log(3^2) [(3)^(-1/2)]
=[(-1/2)/2]log2 2 + [(-1/2)/2]log3 3
=-1/4 - 1/4
=-1/2

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