Take the left hand to √ 2, 0 √ and the right hand tangent as an example.

When h=√2, the left angle A 1HO is 45 degrees.

When h=√3, the right-angle EHO is 45 degrees, and e is the right tangent point.

As h rises, both angles will decrease.

When h decreases (h is greater than 0), both sides will increase.

Therefore, when h is between root 2 and root 3.

The left end point angle will decrease and the right tangent angle will increase.

So there must have been a moment.

The decrease on the left is equal to the increase on the right.

At this time, the total is 90.

The calculation is correct, and the difficulty is not great.

This question is not rigorous enough.