Algebra 2 chapter 13 final
30-60-90 triangle
- Across from 30 = 1 - Across from 60 = √3 - Across from 90 = 2
45- 45- 90 triangle
- Across from 45 = 1 - Across from 90 = √2
Law of Cosines
- a^2 = b^2 + c^2 -2ab cos A
cotangent
- cot - 1 / tan - adjacent / opposite
Cosecant
- csc - 1 / sin - hypotenuse / opposite
Secant
- sec - 1 / cos - hypotenuse / adjacent
Finding the exact of each trig function
1. Draw angle 2. Form a triangle by drawing a line to the x-axis 3. Find the reference angle and label the sides of your triangle 4. Find the value of the trig function 5. Determine the sign
Finding the terminal side of Ø
1. Plot the ordered pair 2. Draw a right triangle to the origin and the x-axis 3. Ø is always at the origin 4. Use a^2 + b^2 = c^2 to find the hypotenuse 5. Now finally find all the trig functions
SSS
1. Use the law of cosines to find the largest angle 2. Use the law of sines to find the 2nd angle 3. Use the triangle angle sum theorem to find the 3rd angle
SAS
1. Use the law of cosines to find the missing 3rd side 2. Use the law of sines to find the smallest angle 3. Use the triangle angle sum theorem to find the 3rd angle
Law of sines
Sin A / a = Sin B / b = Sin C / c
To convert to degrees
multiple 180 / π
To convert to radians
multiply π / 180
Tangent
opposite / adjacent
Sin
opposite / hypotenuse
Cosine
adjacent / hypotenuse