All Junior Cert Mathematics posts
• #### Cos sin tan Lukee98

Can anyone help me with the sin cos and tan thing i was out when we were learning this so i barely know it!!

1. #### MysticManiac

Well not really, but I think that's for Paper 2 so you don't need to worry about it til Monday. I could be wrong though

2. #### Anon1099

Its Trigonometry. Use this mnemonic: Oh Hell Another Hour Of Algebra or SOH CAH TOA

In a right angled triangle, the longest side is always the Hypotenuse. The side that is literally adjacent to the the angle u r to find is known as the adjacent(NB This is NOT the 90 degree angle of the triangle). The side opposite the angle are to find is known as the opposite. Try draw this out for yourself , so that you can actually visualise it.

SOH CAH TOA

S=SIN

say if they ask you to find sin30, this basically means you put the opposite of the angle you have(which will be 30 degrees in this case) OVER the hypotenuse you have.

It is the same with Cos and Tan.

C=COS which is A over H

T=TAN which is Opposite over Adjacent.

In a case were u r asked to find the SIN or COS of something, Hypotenuse is needed. If its not in the Q try use Pythagoras.

Now, if they give you all the sides and ask u to kind the named angle (Not 90 degrees), you use ur calculator do the inverse of what ur trying to find (SIN, COS,TAN).

Im not the best at explaning but i really hope it helped ya :)

3. #### MarianZefi

Paper 1 maths?

4. #### m.cullen

no paper 2 maths