Lesson 1.3 Rt. Trigonometry (continued) Sin = opp/hyp Cos = - - PowerPoint PPT Presentation

Lesson 1.3 Rt.  Trigonometry (continued)

 Adjacent Side Opposite Side

Sin  = opp/hyp Cos  = adj/hyp Tan  = opp/adj Csc  = hyp/opp Sec  = hyp/adj Cot  = adj/opp

Ex 4: Use the given function value(s), and trig identities (including the co-function identities) to find the indicated trig function.

• A. sin 60º = 3/2,

cos 60º = 1/2 1.) tan 60º 2.) sin 30º 3.) cos 30º 4.) cot 30º

60°

√3 2 1 = opp/adj = cos 60° = 1/2 = sin 60° = √3/2 = tan 60° = √3 = √3

(cofunctions) (cofunctions) (cofunctions)

Ex 4 (continued): Use the given function value(s), and trig identities (including the co- function identities) to find the indicated trig function. 4.) sin(90 - ) 3.) cot  2.) sin  1.) sec 

• B. cos  = 1/3

= 3/1 = 3 = 2√2/3 √8 = 1/2√2 = √2/4 = cos  = 1/3

 1 3

=2√2

(cofunctions)

Ex 5: Evaluate the trig function by memory or constructing an appropriate triangle for the given special angle.

• A. cos 60º
• B. csc 30º

Homework: p.156 #18-28 even

• C. sin 45º
• D. cot 45º

 1 2  1 30 sin



 1 1 2

 2

 2 2

 1

Cofunctions