The expression beside doesn’t equal to 2/2/1/2/2, but ((2/2)/(1/2))/2. To comprehend it better, notice the difference in length in each fraction line and look up on http://www.mathsisfun.com/fractions_division.html for further understanding.
All of these only applied on a Right-Angled Triangle.
“Opposite” is opposite to the angle θ
“Adjacent” is adjacent (next to) to the angle θ
“Hypotenuse” is the long one
An easy way to remember trigonometry formulas is to use the triangle method.
Basically, all you do is write SOH, CAH, TOA in three triangles as shown above.
SOH >> Sn A = Opposite / Hypotenuse
CAH >> Cos A = Adjacent / Hypotenuse
TOA >> Tan A = Opposite / Adjacent
– SOH >> Opposite = sin A x Hypotenuse.
– CAH >> Adjacent = cos A x Hypotenuse.
– TOA >> Tan A = Opposite / Adjacent.
Here’s simple image to help remembering every trigonometry special angles.
Why are these functions important?
– Because they let you work out angles when you know sides
– And they let you work out sides when you know angles