Feroz's Blog

I was absent the day we went over 10-2, so I'm going to attempt to learn it via this blog post. Hopefully.

According to everyone else, it's the same as 10-1 but instead of cos and sin, it deals with tan and cot. The formulas are:

tan(a + b) = tan(a) + tan(b)/1 - tan(a)tan(b)
tan(a - b) = tan(a) - tan(b)/1 + tan(a)tan(b)

cot(a+b) = 1 - cot(a)cot(b)/cot(a) + cot(b)

So then, an example:

tan(27) + tan(18)/1 - tan(27)tan(18)

Using this, we know we have to use the first formula I posted, since it matches the problem.

So tan(a + b) = tan (27 + 18) = 45

And tan(45) = 1

There you go. This seems pretty simple, though I'm sure I'm missing something.