1. ## Using Trigonometric Identity

a) Find the exact value of sin 135 by using sin (180 – 45)

b) Find the exact value of sin 225 by using sin (270 – 45)
b) Use the value of sin 225 found in b to find sin (–15) by using sin (225 – 240)

2. Recall $\displaystyle \sin (180-\theta) = \sin \theta$

so

$\displaystyle \sin 135 = \sin (180-45) = \sin 45 = \dots$

3. Originally Posted by pickslides
Recall $\displaystyle \sin (180-\theta) = \sin \theta$

so

$\displaystyle \sin 135 = \sin (180-45) = \sin 45 = \dots$

but how i can solve part c of the question

4. Are expected to solve the problem by using

sin(A-B) = sinAcosB - cosAsinB ?