February 22, 2010
5.3
Sum and Difference Formulas
sin(u+v) = sinu cosv + cosu sinv
sin(u-v) = sinu cosv - cosu sinv
cos(u+v)= cosu cosv - sinu sinv
cos(u-v) = cosu cosv + sinu sinv
tan(u+v) = tanu + tanv
1 - tanu tanv
tan(u-v) = tanu - tanv
1 + tanu tanv
February 22, 2010
Write the expression as the sine, cosine, or tangent of an
angle.
1. cos94ocos18o+sin94osin18o
2. tan 3x - tan 2y
1 + tan 3x tan 2y
February 22, 2010
Examples. Simplify.
1. cos(
-x)
February 22, 2010
2. Confirm the cofunction identity.
cos(
2
-x)
= sin x
February 22, 2010
3. Find the exact value of sin 15.
February 22, 2010
4. Find the exact value of cos12
February 22, 2010
5. Find the exact value of sin (u + v) given:
sin u = 4
5
cos v = -12
13
0<u<
2
<v<
2