Weekend Wiki Party 8 - Trigonometry

This week our wiki project is to improve some of the trigonometry pages on the site. Thanks to your contributions from previous wiki weekend parties, we have collectively made hundreds of edits to wiki pages and helped Brilliant's 1,000,000+ FB followers learn, collaborate, and solve problems together!

To participate, just jump in and write something on one of the following pages, and then leave a comment to let us know that you contributed. To guide you in crafting the wikis, we have included section outlines, identities in need of proofs, and examples in need of solutions. We need your help to replace the many "???" throughout these wikis with your brilliant proofs and solutions. Or feel free to add a new section or submit your own example. Every contribution helps!

Note by Calvin Lin
5 years, 5 months ago

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MathAppears as
Remember to wrap math in $$ ... $$ or $ ... $ to ensure proper formatting.
2 \times 3 $2 \times 3$
2^{34} $2^{34}$
a_{i-1} $a_{i-1}$
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\sqrt{2} $\sqrt{2}$
\sum_{i=1}^3 $\sum_{i=1}^3$
\sin \theta $\sin \theta$
\boxed{123} $\boxed{123}$

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Is there a sum to product identity for $\tan x+\tan y$? The only one I can think of is $(\tan(x+y))(1-\tan x\tan y)$, or maybe something like $\frac{\sin(x+y)}{\cos x\cos y}$.

Oh, and, could someone please give me a link to the wiki from where I can start studying matrices? Can't find it. Thanks :)

- 5 years, 5 months ago

There isn't a "nice" version of it. Another way of writing it, where we only use $\tan$, is $\tan x + \tan y = \tan ( x + y) ( 1 - \tan x \tan y )$. Do you see how to get there from what you have?

We haven't started on the matrices skills as yet, because we rather focus on filling out existing areas first.

Staff - 5 years, 5 months ago

Okay thanks! Yeah, I can get to the formula.

- 5 years, 5 months ago

That should be $\tan(x+\color{#D61F06}{y})(1-\tan x\tan y)$

- 5 years, 5 months ago

Thanks! fixed.

Staff - 5 years, 5 months ago

sir, can we add wiki on INVERESE TRIGONOMETRY also???

- 5 years, 5 months ago

There are already pages on inverse trigonometry, functions, identities and graphs(this one is empty). So you don't need to make new Wikis (unless it's a completely new subtopic you wanna write about), you can go through these and add any knowledge they lack.

- 5 years, 5 months ago

Sure. Add a wiki on any topic you like. $\ddot\smile$

- 5 years, 5 months ago

Yeah sure.....I'll collect all the required wikis for the topic and post it tomorrow

- 5 years, 5 months ago

Staff - 5 years, 5 months ago

Sir, i've added a wiki. can u see if its fine

- 5 years, 5 months ago

- 5 years, 5 months ago

I have an advice. Use degrees instead of radians. The page is for newbies who might not have studied about radians. Thanks. $\ddot\smile$

- 5 years, 5 months ago

Oh okay! Good suggestion, thanks.

- 5 years, 5 months ago

Thanks! Keep it up!

- 5 years, 5 months ago