Function naming incorrect/missing

[pinkynrg]

I noticed that a few functions in functional.rb have not the same name as the Atoms in the yml file, such as:

• functional.rb => tan100, derived_unit.rb => 100tan
• functional.rb => ph, derived_unit.rb => pH

Also there are some ":function_code"s that has not been implemented in functional.rb such as:

• hpM
• hpQ
• sqrt

[phlegx]

Hi @pinkynrg can you implement the functions and make a PR please?

[pinkynrg]

I'm try my best to google the correct formulas.