导线代号
A
B
C
D
E
F
G
导线长度(m)
1.0
0.5
1.5
1.2
导线横截面积(mm2)
3.0
0.6
1.8
导线材料
锰铜
钨
镍铬
函数f(x)=(1+3tanx)cosx的最小正周期为( )
—I will have an important test tomorrow. I feel stressed now.—__________ and believe youself. You will pass it.