2. Questions 2, 3, 4 and 1 have similar formats, namely:
Solution: When t=? , ABCD is a diamond, which is proved as follows (or for the following reasons):
(Write proof process)
3.(t is there a value that makes ABCD diamonds? If it exists, request the value of t; If it does not exist, please explain why. )
Solution: existence (or non-existence), generally this kind of topic will be existence.
When t=? When ABCD is a diamond,
Taking the value of t as a known condition, it is proved that ABCD is a diamond.
Of course, here you need to guess the value of t and then prove it.
By the way, I like to write if ABCD is a diamond when I do this kind of problem, then. . . Is this the correct format? )
This format is wrong, and the conditions and conclusions are reversed. We should take the t value as a known condition to prove that ABCD is a diamond.
PS: I'm a math teacher.