0
$\begingroup$

I'm trying to demonstrate:

$$ \sin(π/6) = \sin(30º) = 1/2 $$

Which property or assumption I should use to start?

$\endgroup$
3
  • 4
    $\begingroup$ Use a equilateral triangle. $\endgroup$
    – Ana S. H.
    Sep 10 '16 at 16:05
  • 3
    $\begingroup$ it depends how you have defined the sine function $\endgroup$
    – Dan Rust
    Sep 10 '16 at 16:05
  • 1
    $\begingroup$ I'll check, thank you. @Ana $\endgroup$ Sep 10 '16 at 16:06
3
$\begingroup$

Hint for other solution: $$1 = \sin(\pi/2) = \sin(3(\pi/6)) = \text{some polynomial}(\sin(\pi/6)).$$ (for the last $=$ apply some trigonometric formula)

$\endgroup$
3
$\begingroup$

If you consider an equilateral triangle ABC whose each side is "a",each angle will be 60 degrees,draw perpendicular from point A on side BC as AD, angle DAB=angle DAC=30 degrees.on calculating geometrically you will get BD=a/2,also AB=a. sinBAD = sin(π/6) = BD/AB =(a/2)/a = 1/2.

$\endgroup$
4
  • $\begingroup$ What is mathjex $\endgroup$ Sep 10 '16 at 16:40
  • $\begingroup$ Is it similar to latex? $\endgroup$ Sep 10 '16 at 16:43
  • 1
    $\begingroup$ @SathasivamK Yes, and it's called MathJax. $\endgroup$ Sep 10 '16 at 16:44
  • $\begingroup$ OK ...alright.. $\endgroup$ Sep 10 '16 at 16:45

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.