10-2

Section 10-2

This week in advanced math we started section 10-2. Section 10-2 is similar to section 10-1. The only difference is we use tangent formulas instead of sine and cosine formulas. There are two formulas you need to remember for tangent:

Sum Formula:
Tan (alpha + beta) = tan alpha + tan beta/1 – tan alpha tan beta

Difference Formula:
Tan (alpha – beta) = tan alpha – tan beta/1 + tan alpha tan beta

Here’s an example:

Example:
Simplify this difference formula

Tan 140 degrees - Tan 95 degrees/ 1 + Tan 140 degrees Tan 95 degrees
1. Replace the right side of the formula with the left
2. Tan (140 degrees – 95 degrees)
3. When you subtract them you get Tan 45 degrees. Tan 45 degrees is in your trig chart as 1.

*Cotangent is the reciprocal of tangent. Reciprocal means opposites so you just flip problem and use the same formula.