What is the connotation and denotation of confident

The denotation of a word is its definition, so the denotation of the word confident is having a feeling or belief that you can do something well or succeed at something.
The connotation is your feeling about the word confident, so it usually has a positive connotation - it's a good thing being confident. 

8.7 degrees celsius and 15.6 degrees fahrenheit

The disturbance is only parallel to the motion of the wave.