Basic Trig Graphing Open Middle Problem

Using the digits 1-9 no more than one time each, fill in the blanks below to make a true statement.

Using the digits 1-9 no more than one time each, fill in the blanks below to make a true statement.

Drag number tiles in the boxes below to make all the statements above true.

Can you find solution different from the one above? Give it a try.

What made this problem really challenging? Describe.