# Trigonometry

Is there a easy way of resolving trigonometry questions? theres a long method that i know but i need faster ones.

Posted Sun 29th May, 2011 @ 21:43 by Mohamed Farah
Edited by Mohamed Farah on Fri 3rd June, 2011 @ 13:52

## 4 Answers

with right-angled triangles there's: a^2 = b^2 + c^2 to find out the length of a side if the other two are known.

if an angle and a side are known then you have to label the triangle with hypotenuse (longest, slanted side), opposite (angle (not right angle)) and adjacent the to the angle. and then if you just sick with the S o/h, C a/h, T o/a. S being sin, C being cos and T being tan. then do eg., tan36(degrees) = x/10 so x = 10tan36. if you need to fin out an angle you'll have to use the tan-1 function.!

it doesn't take long at all if you know what you're doing :) do a few practice questions and it'll all come you!

also do you need to know the sine and cosine rule? :) x

Answered Mon 30th May, 2011 @ 10:42 by Kelly:)

For the sine = opposite/hypotenuse and cosine = etc.. u can remember it by  SOHCAHTOA : its really lame but easy to remember,

also the sine rule is reallyy easy its just

sine a/A= sine b / B = sine c = C, where lower case is the angle and upper case is the side length opposite it , i hate  the cosine rule so im not gna mention it ;)

Answered Mon 30th May, 2011 @ 11:34 by Lamise Hassan
Edited by Lamise Hassan on Mon 30th May, 2011 @ 11:35

What Kelly said, the SOH CAH TOA mnemonic should be sufficient to learn for the exam, for the cosine and the sine rule should be given to you on the first page of the exam, if you are taking the Edexcel exam like I am ;)

Answered Mon 30th May, 2011 @ 12:02 by Sagz

As far as the sides are concerned , if you are using the opposite side, then it has to be either Sin or Tan, reduce to tan if you have the adjacent.  Otherwise use Cos.

Of course there are the non-right-angled triangles as well, so Sine Rule or Cosine rule hav eto be used then

Answered Mon 30th May, 2011 @ 17:54 by Arron Beckett