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Sin, Cos and Tan

February 3rd, 2008 admin Leave a comment Go to comments

This is the basics of using sine, co-sine and tangent for a right angled triangle. To do this you’ll probably need a scientific calculator

Trigonometry Triangle

To perform calculations we are going to use the triangle above.
The three main relationships are:

Tan(x) = o/a
Sin(x) = o/h
Cos(x) = a/h

so if h = 5 and x = 30
a = Cos(30)h = 4.330

We can also use a inverse of the functions
ie) x = tan-1(o/a)
x = sin-1(o/h)
x = cos-1(a/h)

so if o = 5 and a = 10
x = tan-1(5/10) = 26.565

Using this information we can work out any side or angle in a right angled triangle as long as we have to other pieces of information (like a side and a angle or 2 sides). This is used a lot in resolving forces in physics and allows us to derive some other more complex equations.

Soon ill be adding a maths section to my site Breakingwave

  1. March 10th, 2008 at 14:22 | #1

    Hello, I am still trying to make sense of this. I have looked through weveral sites and think the format you have to start will be understandable for me. I will reaccess this when i have more time. Thanks, I am looking forward to becoming math competent!

  2. Fansci
    May 20th, 2008 at 00:32 | #2

    thanks for putting this up. I already understand it in geometry, but we are ready to take our sols so I had to re-remember it!
    this is very useful.
    thank you.

  3. Anders
    May 23rd, 2008 at 06:00 | #3

    Thanks for putting this information up, I have read a lot of math but hasen“t used any in a long time. So this just what I needed to rember how cos, sin and tan works. Thanks

  4. May 27th, 2008 at 15:34 | #4

    Thanks, was looking for this.

  5. Anonymous
    July 9th, 2008 at 15:22 | #5

    wtf

  6. August 27th, 2008 at 15:16 | #6

    thank you so much.!
    you know me bella, i cant understand math very well.
    thanks

  7. Bon
    September 11th, 2008 at 08:28 | #7

    Sorry, my stupif lil bro said that. Awesome site! Thanks for all the tips, really helped me understand how Sin Cos and Tan work again. Very useful!!! :)

  8. Anonymous
    November 18th, 2008 at 02:10 | #8

    thanks so uch my math teacher SUCKS, he doesn’t explain it right.

  9. Nadya Fermega
    December 21st, 2008 at 15:54 | #9

    Whether the trig identity (sinx)^2+(cosx)^2=1 only can be created using a triangle?

  10. Denaya Lesa
    December 21st, 2008 at 18:43 | #10

    Nadya, you need to complete your question, whether the trig identity holds only for a right angled triangle. If not, can this forum gives other example the proof of (sinx)^2+(cosx)^2=1 without using pythagoras formula for the triangle?Thx.

  11. February 10th, 2009 at 03:12 | #11

    this is al so confusing lol

  12. sal g
    April 3rd, 2009 at 01:09 | #12

    i still dont understand

  13. Oliver
    October 29th, 2009 at 22:58 | #13

    Thanks heaps, I do physics but not maths so I don’t get this stuff. Figures…

  14. admin
    October 30th, 2009 at 10:09 | #14

    @Oliver
    Thanks for visiting glad I could help

  1. February 13th, 2008 at 17:10 | #1
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