AB-AD≤BD≤AB+AD, if and only if A, B and D are on the same straight line, take the equal sign.
The minimum value is (root number 10)- (root number 2), and the maximum value is (root number 10)+ (root number 2).
Draw a graph, and you can see that when the minimum value is ∠ PBC = 45, the maximum value is ∠ PBC = 135.
One is to divide courses into basic courses, expanding courses and research courses, which is ()
Courses are divided into basic courses, expanding courses and resear