单选题-9cos2θ- 9sin2θ= ______.A0B1C-1D9E-9
单选题
-9cos2θ- 9sin2θ= ______.
A
0
B
1
C
-1
D
9
E
-9
参考解析
解析：
-9cos2θ- 9sin2θ= -9(cos2θ+ sin2θ)= -9(1) = -9
-9cos2θ- 9sin2θ= -9(cos2θ+ sin2θ)= -9(1) = -9
相关考题：
单选题9sin2 x + 9cos2 x = ______.A1B-1C9D-9E0