cos7π /12sin35π/12sin(π/4-α)+cos(π/4-α)

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cos7π/12sin35π/12sin(π/4-α)+cos(π/4-α)cos7π/12sin35π/12sin(π/4-α)+cos(π/4-α)cos7π/12sin35π/12sin(π/4

cos7π /12sin35π/12sin(π/4-α)+cos(π/4-α)
cos7π /12
sin35π/12
sin(π/4-α)+cos(π/4-α)

cos7π /12sin35π/12sin(π/4-α)+cos(π/4-α)
cos7π /12=cos105=-(根号6+根号2）/4
sin35π/12=(根号6+根号2）/4
sin(π/4-α)+cos(π/4-α)
=根号2/2(cosa-sina+sina+cosa)
=根号2*cosa

说实话。。没看懂呢。。。要求什么？