10-2

Formulas:

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

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

Ex. 1.) Find tan (a + b) If a is 2/3 and b is 1/2.

-You would use the first formula, tan(a)+tan(b)/1-tan(a)tan(b).

-It would be 2/3 + 1/2/1-2/3(1/2).

-You have to get a common denominator for the top and bottom, so

it would then become 2/2 (2/3) + 1/2 (3/3)/1-2/2 (2/3)(1/2) 3/3

-It would then become 4/6 + 3/6/ 4/6, making it 7/6/4/6, which equals 42/21.

you have to get the numbers to have a common deno so you can solve it, so you have to multiply the 3 by 2 and the 2 by 3. you will get 4/6 and 3/6. Then you have to multiply the bottom numbers so its 1-2/6= 6/6-2/6= 4/6. 1 is the same as 6/6, so it's 6/6-2/6=4/6.

Then its 7/6/4/6. so then you sandwich it. 7 times 6 and 6 times 4. so it's 42/21. then you have to simplify it. so the answer is 2.