答:
1)
g(x)=log2(1-x^2)的定义域为N
1-x^2>0,-1-3/4
2)
a>-(2^x+1)/(2^x)^2=-1/2^x-1/(2^x)^2
-1/2^x-1/(2^x)^2随2^x的增大而增大
x趋于无穷时,-1/2^x-1/(2^x)^2=0
x趋于负无穷时,2^x趋于0,-1/2^x-1/(2^x)^2趋于负无穷
x=-1时,2^x=1/2;-1/2^x-1/(2^x)^2=-2-4=-6
所以:a>-6时,M的取值至少包括x=-1+使得M∩N≠空集
所以:a>-6