#1 and #3 are proven correctly.
To see why #2, and #4 are wrong:
For #2:
For #4:
You may want to refer to: Hyperbolic function as these proofs are very easy to verify.
#1 and #3 are proven correctly.
To see why #2, and #4 are wrong:
For #2:
For #4:
You may want to refer to: Hyperbolic function as these proofs are very easy to verify.