Question

若f(x)=x²-ax在[1,2]上递增,g(x)=ax-1/x+1在[1,2]上递减,求a的范围

高一数学. 急!快!拜求!
1.若f(x)=ax+1/x+2在去甲（-2,+无穷）单调递增,求a的取值范围
2.若f(x)=-x^2+2ax与g(x)=a/x+1在区间【1,2】上是单调减函数,求a的取值范围.
要有过程哦！~

Answer 1

1.f'(x)=a-1/x^2,单调递增的话,f'(x)≥0,则a≥1/x^2.已知X在区间（-2,+无穷）单调递增.可知a>1/4
2.f'(x)=2x+2a≤0,a≤-x,x在区间【1,2】,可知a≤-2;
g'(x)=-a/x^2≤0,a≥0