Chapter 5

• trig identity 1: $sin^2x+$$cos^2x=$$1$
• trig identity 2: $1+$$tan^2x=$$sec^2x$
• trig identity 3: $1+$$cot^2x=$$csc^2x$
• sine sum formula: $sin (a+b) =$$sin a cos b +$$cos a sin b$
• sine difference: $sin (a-b) =$$sin a cos b - cos a sin b$
• cosine sum: $cos (a+b) =$$cos a cos b - sin a sin b$
• cosine difference: $cos (a-b) =$$cos a cos b +$$sin a sin b$
• tangent sum: