8-4 Review

This week I am going to review with you all the material that we learned back in September. I am going to show you all how to work problems by using the relationships among trig functions. There are some formulas that you need to know before you work any problems.
Formulas:
• Sinx / cosx = tanx
• Cosx / sinx = cotx
• Cscx = 1 / sinx
• Secx = 1 / cosx
• Cotx = 1 / tanx
• Sin^2x + cos^2x = 1
• 1 + tan^2x = sec^2x
• 1 + cot^2x = csc^2x
• Sinx = cos (90 degrees – x)
• Cosx = sin (90 degrees – x)
• Tanx = cot (90 degrees – x)
• Cotx = tan (90 degrees – x)
• Secx = csc (90 degrees – x)
• Cscx = sec (90 degrees – x)
There are also some steps that you need to follow loosely.
Steps:
1. Algebra
2. Identites; try the Pythagorean identity first, then, if it helps, move everything to sin and cos
3. Then more Algebra
4. Continue with steps 1-3
Example: (secx – 1) (secx + 1)
• Sec^2x – 1
• Tan^2x

-Braxton