1、两角和与差的正弦、余弦和正切公式第二课时 练习1.cos 75cos 15-sin 75sin 15的值等于(). A.12 B.-12 C.0 D.12.化简2cos x-6sin x等于().A.22sin6+x B.22cos6-xC.22sin3-x D.22cos3+x3.(多选题)下列说法正确的有().A.,使sin(+)=sin +sin B.,有sin(+)sin(-)=sin2-sin2C.,使cos(+)=cos +cos D.,有cos(+)cos(-)=cos2-cos24.cos-174-sin-174的值是().A.2 B.-2 C.0 D.225.函数f(x)=s
2、inx+4-sinx-4是().A.周期为的偶函数 B.周期为2的偶函数C.周期为的奇函数 D.周期为2的奇函数6.已知sin =sin+3+13,则cos+6的值为().A.13 B.-13 C.233 D.-2337.若sin34+=513,cos4-=35,且0434,求cos(+)的值.8.(多选题)函数f(x)=sin x+3cos x-1的().A.图象的对称中心为23+k,-1(kZ)B.图象的对称轴方程为x=-3+k(kZ)C.单调递增区间为-56+2k,6+2k(kZ)D.最大值是3,最小值是-39.4cos 10-cos10sin10=().A.-2 B.2 C.-3 D.
3、310.设,0,且满足sin cos -cos sin =1,则sin(2-)+sin(-2)的最大值为,最小值为.11.已知0,2,-2,0,且cos(-)=35,sin =-210,求sin .12.已知cos =55,sin(-)=1010,且,0,2.(1)求cos(2-)的值;(2)求的值.参考答案1.C2.D3.ABC4.A5.B6.B7.【解析】0434,3434+,-24-0,所以0-2.所以sin =1-cos2=255,cos(-)=1-sin2(-)=31010,cos(2-)=cos+(-)=cos cos(-)-sin sin(-)=5531010-2551010=210.(2)cos =cos-(-)=cos cos(-)+sin sin(-)=5531010+2551010=22,又因为0,2,所以=4.
