sinπ/12cos5π/12等于

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sinπ/12cos5π/12等于sinπ/12cos5π/12等于sinπ/12cos5π/12等于积化和差公式:sinAcosB=[sin(A+B)+sin(A-B)]/2sinπ/12cos5π

sinπ/12cos5π/12等于
sinπ/12cos5π/12等于

sinπ/12cos5π/12等于
积化和差公式:
sinAcosB=[sin(A+B)+sin(A-B)]/2
sinπ/12cos5π/12=[sinπ/2+sin(-π/3)]/2=(1-√3/2)/2=1/2-√3/4

sinπ/12cos5π/12
=sinπ/12sin(π/2-5π/12)
=(sinπ/12)^2
=[1-cos(2*π/12)]/2
=(1-cosπ/6)/2
=(2-√3)/4