Merge pull request #9 from takehilo/refactor-ex3

prettify output

use minimize function

prettify output

Merge pull request #8 from takehilo/refactor-ex2

use minimize function

prettify output

update plot code

use minimize function

update plot code

prettify output

Merge pull request #7 from takehilo/refactor-ex1

update plot code

prettify output

update plot code