集合A={X/-1≤X≤a,a>1},P={Y/Y=X+1,X∈A},Q={Y/Y=X²,X∈A}.若Q∩P=Q,求实数a的取值范围.
问题描述:
集合A={X/-1≤X≤a,a>1},P={Y/Y=X+1,X∈A},Q={Y/Y=X²,X∈A}.若Q∩P=Q,求实数a的取值范围.
答
P:y∈[0,a+1]
Q:y∈[0,a²]
∵Q∩P=Q
∴a²≤a+1
∴a∈[(1-√5)/2,(1+√5)/2]