如图,将△ABC绕点C(0,1)旋转180°得到△A′B′C,设点A′的坐标为(a,b),则点A的坐标为( )
A:(﹣a,﹣b)
B:(﹣a,﹣b+2)
C:(﹣a,﹣b+1)
D:(﹣a,﹣b﹣1)
已知sin(a+π6)=13,则cos(2a﹣2π3)的值是( )
看图,读一读,选择适当句子补全对话。
A. She can't see her pet dog.
B. I'm full now.
C. Can I have some water?
D. I am hungry, Mum.
E. I am sad.
已知数列{an}为等差数列,数列{bn}满足bn=an+n,若b2,b5,b11成等比数列,且b3=a6.
求an,bn;
(2015•百色)使用手机通话时,信息的传播是通过____ 波来实现的,这种波在真空中的传播速度是 ____ m/s.