Math Analysis:
Use an appropiate identity to find the exact value of the expression.
12. sin15
13. tan23 + tan22/1-tan23tan22

Question

Math Analysis:
Use an appropiate identity to find the exact value of the expression.
12. sin15
13. tan23 + tan22/1-tan23tan22

anonymous · Answer

12.) sin(45 - 30) = sin 45cos 30 - cos 45sin 30 = (√2/2)(√3/2) - (√2/2)(1/2) = (√6/4) - (√2/4) = (√6 - √2)/4

campbell_st · Answer

this uses sum and difference formula

sin 15 = sin(45 - 30)

            = sin45cos30 - cos45 sin30
           
45 and 30 are exact values which can be substituted into the equations

$$\sin45 = \cos(45) = \frac {1}{\sqrt{2}}$$

$$\sin(30) =1/2   ===========\cos(30) = \frac{\sqrt{3}}{2}$$

campbell_st · Answer

the next question is the expansion of 

tan(23 + 22) = tan (45) = 1

anonymous · Answer

yeah, i got it thx :) nxt question!!! lol

anonymous · Answer

Math Analysis:
Find the indicated trigonometric function for 0 given 0 is an angle in standard position with terminal side defined by the given point.
(-5,12); find cos0

anonymous · Answer

wait i mean

anonymous · Answer

sin^20 + sin0 -1 cos^20