Prelim Maths Trig Extension 1 (1 Viewer)

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Hey guys, can you help me with this question? Thanks.

 

[hit patel]

Try using compound trig method where tan (u) from a/3 is 0<u<120.

 

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Try using compound trig method where tan (u) from a/3 is 0<u<120.

hm...sorry I dont understand. Can you show me what you mean please?

 

[Drongoski]

Actually this is equivalent to the identity:





= RHS

You can simplify your expression by reversing the steps in the above proof; otherwise it is not obvious how one might simplify it.

 

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Actually this is equivalent to the identity:







= RHS

You can simplify your expression by reversing the steps in the above proof; otherwise it is not obvious how one might simplify it.

Thanks. But i havent learnt that formula in school yet. Is there another way of doing it? But thanks for ur help, I also did get the answer too!

 

[hit patel]

Dragon show him what I meant its hard to show it like he shows it you know with the fractions and theta. How do you write what you mean in fractions and using theta????

 

[HeroicPandas]

Actually this is equivalent to the identity:





= RHS

You can simplify your expression by reversing the steps in the above proof; otherwise it is not obvious how one might simplify it.

Sir, there is also another method

Step 1: let u = A/3 (for simplicity)

Step 2: change all tans into sin/cos

Step 3: common denominate, ssimplify

Step 4: u will end up with:



Step 5: notice triple angle formulae (which can be proven by the sine and cosine expansions - compound formulas - just like how Drongoski did for tan3theta






Step 6: finally u change all thetas into A/3, and there u have it

 

[-Dark Light-]

Sir, there is also another method

Step 1: let u = A/3 (for simplicity)

Step 2: change all tans into sin/cos

Step 3: common denominate, ssimplify

Step 4: u will end up with:



Step 5: notice triple angle formulae (which can be proven by the sine and cosine expansions - compound formulas - just like how Drongoski did for tan3theta






Step 6: finally u change all thetas into A/3, and there u have it

YAY, Thanks Heroic!