Mary's holiday blog 2

Review of 10-2

You can't do anything unless you know these formulas:

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

they could tell you something like "suppose tan(.." and you will find an answer by using the full formula, if they tell you to simplify, you will use the opposite side of the equation.

example:

simplify

tan27+tan18/1-tan27tan18

so you know you need to use the other side of the formula

which is tan(a +b)

which is tan (45) which = 1

yay

math is fun...

example 2: tan( x + pie/4)

so you find the formula that matches

so you plug your numbers in.

so you get

tanx+tanpie/4/1-tanxtanpie/4

which simplifies to,

tanx+1/1-tanx

or they could tell you this

"suppose tan alpha=1/3 tan alpha beta=1/2

and then you'll put that straight into the formula and you get:

1/3 + 3/6/1-1/6=1

but if it had said cos alpha = 1/3, you would have to draw out your triangle and take the tan of it.

yeaa!