Sine / Cosine Rules ??? (1 Viewer)

[esos]

I had a test based on those rules. They make me sick. I just cant tell if I should use the sine rule, cosine rule or just SOH CAH TOA>

I've done heaps of research, tried to memorise different types of formulas, but still I couldnt do well in the test.


Please help.

Thanks in advance.

(i know that when you got 2 sides + an angle you use ....., but still the triangles confuse me )

 

[slyhunter]

SOHCAHTOA - Right angled triangles

Sine and Cosine Rule - Non-right angled triangles

 

[frenzal_dude]

I had a test based on those rules. They make me sick. I just cant tell if I should use the sine rule, cosine rule or just SOH CAH TOA>

I've done heaps of research, tried to memorise different types of formulas, but still I couldnt do well in the test.


Please help.

Thanks in advance.

(i know that when you got 2 sides + an angle you use ....., but still the triangles confuse me )

can you give us some examples of the questions you had?

You need to know which sides of the triangle are opposite, adjacent, and hypotenuse. Once you know that, and if can remember sohcahtoa, then using sin cos or tan shouldn't be a problem.

 

[ohexploitable]

SOCAHTOA: right-angled triangles

Sine rule: find an angle given 2 sides + 1 angle OR find a side given 2 angles + 1 side

Cos rule: find a side given 2 sides + 1 angle OR find an angle given 3 sides

 

[tranx]

I dont understand why sine, cosine and tangent are so difficult (unless your doing the taylor series, where it gets confusing) In general you really only have a few conditions you must follow, if your remember them then your sweet for the test. And no matter how much they try and confuse you, just brake down the question and your done.

 

[ohexploitable]

I dont understand why sine, cosine and tangent are so difficult

I'm sorry we're not as smart as you

 

[ohexploitable]

I dont understand why sine, cosine and tangent are so difficult (unless your doing the taylor series, where it gets confusing) In general you really only have a few conditions you must follow, if your remember them then your sweet for the test. And no matter how much they try and confuse you, just brake down the question and your done.

m8

 

[michaeljennings]

God at maths dog at english?

 

[Effekt]

Ok this is how i look at it.

Check what information you are given in the triangles eg 2 angles, 2 sides or w.e then look at what you are trying to find and mark is X
Look at the formulas and check what information you need then see what information you have and pick a formula.

OR you can do this which is what my teacher told us to remember.

(unknown side)2 = (side 1)2 + (side 2)2 - 2(side 1) (side 2) cos (angle b/w side 1 and side 2)

cos of unknown angle = (side 1)2 + (side 2)2 - (side 3)2 divided by 2 x side 1 x side 2

 

[nightweaver066]

Two different scenarios for each. By the way, the dots are the known angles.

Sine Rule scenarios:

Solve this using:

Solve this using:


Cosine rule scenarios:

Solve this using:

Solve this using:


Edit: Just realised how old this is.. Wasted effort..