The explanation of the Law of Cosinus

Law of CosinusSource:
wikipedia.org
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SOHCAHTOA

All of these only applied on a Right-Angled Triangle.

adjacent-opposite-hypotenuse

“Opposite” is opposite to the angle θ
“Adjacent” is adjacent (next to) to the angle θ
“Hypotenuse” is the long one

trig-equations

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

Examples :
– 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.

trig

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

Source:
mathsisfun.com
tutorbee.com.au