1 等式sin(π/2+3π/2)=sinπ/2+sin3π/2( )成立。 (a) 一定 (B) 不一定 (C) 一定不答( ) 2 若一个平面内的一条直线垂直于另一平面内的两条直线,则这两个平面( )互相垂直。 (A) 一定 (B) 不一定 (C) 一定不答( )。 3 若y=f(x)是增函数,则y=f(1-2x)( )是增函数 1 The equation sin(π/2+3π/2)=sinπ/2+sin3π/2() holds. (a) Certain (B) Not necessarily (C) Certainly not () 2 If a line in one plane is perpendicular to two lines in another plane, the two planes () are perpendicular to each other. (A) Certain (B) Not necessarily (C) Certainly not answered ( ). 3 If y=f(x) is an increasing function, y=f(1-2x)() is an increasing function