(Sin105-根号3乘cos105)(根号3乘cos15-sin15) 求值

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(Sin105-根号3乘cos105)(根号3乘cos15-sin15) 求值

(Sin105-根号3乘cos105)(根号3乘cos15-sin15) 求值
(Sin105-根号3乘cos105)(根号3乘cos15-sin15) 求值

(Sin105-根号3乘cos105)(根号3乘cos15-sin15) 求值
1.
原式=2*(1/2*sin105-3^(1/2)/2*cos105)
=2*(cos60*sin105-sin60*cos105)
=2*(sin(105-60))
=2^(1/2)
2.
原式=2*(3^(1/2)/2*cos15-1/2*sin15)
=2*(cos30*cos15-sin30*sin15)
=2*(cos(30+15))
=2^(1/2)
其中2^(1/2)表示根号2

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