How to go about using tangents in Java? -


i bored , wanted practice java coding skills. made program finds area of polygon based on know (radius, perimeter, apothem).

here's portion:

static void pentagon() {     system.out.println("select know");     system.out.println("[1]perimeter\n[2]apothem\n[3]radius");     info = input.nextint();      if (info == 1) {         system.out.println("what perimeter of pentagon?");         double per = input.nextdouble();         double apothem = per * .137638192;         double answer = apothem * per * .5;         system.out.println("the area of pentagon " + answer + " square units.");     } else if (info == 2) {         system.out.println("what apothem of pentagon?");         double apothem = input.nextdouble();         double per = apothem / .137638192;         double answer = apothem * per * .5;         system.out.println("the area of pentagon " + answer + " square units.");     } else if (info == 3) {         system.out.println("what radius of pentagon?");         double rad = input.nextdouble();         double per = rad / .1701301617;         double apothem = per * .137638192;         double answer = apothem * per * .5;         system.out.println("the area of pentagon " + answer + " square units.");     } }

due problem decimals (ratio of apothem perimeter) had figure out myself, code few useful ones.

if knew how use tangents, figure out.

ex: double apothem = length / tan(360/10/2)

(an apothem of decagon) can show me how code previous line?

the recomended way use java.lang.math.tan(double a)

double apothem = 1 / java.lang.math.tan( (2*java.lang.math.pi)/(10*2))

unless there reason why need extraordinary precision , not provide it. may able find third party alternative.


Comments

Post a Comment

Popular posts from this blog

jquery - How do you format the date used in the popover widget title of FullCalendar? -

Image
in fullcalendar, how format date used in popover widget title when clicking '+n more'? code: <div class="fc-popover fc-more-popover"> <div class="fc-header fc-widget-header"> <span class="fc-close fc-icon fc-icon-x"></span> <span class="fc-title">tuesday, april 7</span> ... </div> ... </div> you use daypopoverformat that. determines date format of title of popover created eventlimitclick option. must date formatting string. default value "dddd, mmmm d" english , "ll" other languages.
Read more

asp.net mvc - SSO between MVCForum and Umbraco7 -

i need integrate sso between mvcforum (forum of company) , umbraco7 (manages cms company). however struggling shared authentication work. tried several ways suggested on other threads still not running expected. here did: 1. in mvcforum (forum.mywebsite.com) 1.1. machine key in web.xml: <machinekey validationkey="the same key umbraco7" decryptionkey="the same key umbraco7" validation="sha1" decryption="aes" /> 1.2. authenticate forms in web.xml <forms name="my-sso-auth" protection="all" path="/" timeout="43200" domain="forum.mywebsite.com" loginurl="/members/logon" enablecrossappredirects="true" /> 2. in umbraco7 (news.mywebsite.com) 2.1. machine key in web.xml: <machinekey validationkey="the same key mvcforum" decryptionkey="the same key mvcforum" validation="sha1" decryption="aes" /> 2.2. a...
Read more

Python Tkinter keyboard using bind -

i have problem using bind option can click button in keyboard, , call function once key pressed. tried taking other codes have similar purpose , saw i'm doing pretty same, though still have problem must've missed. thankful if me this. here's code: # -*- coding: utf-8 -*- #imports tkinter import * pil import imagetk, image import time import tkmessagebox #===========================================================================================================================================# #tkinter class class app(frame): def __init__(self, master=none): frame.__init__(self, master) self.pack() #===========================================================================================================================================# #game pieces classes class board: def __init__(self, rows = 7, columns = 6, picture_height = none, picture_width = none): self.rows = rows self.columns = columns self.picture ...
Read more