This is the rule of sums of trig identities. It says that sin(a + b) = sina*cosb+sinb*cosa. Set up your right triangles. In a 30-60-90 triangle, the side across from the 60 angle is the square root of 3, the side across from the 30 is 1, and the hypotenuse is 2. In a 45-45-90 the sides across from the 45 degree angles are 1 and the hypotenuse is square root of 2. With that being said, the sin of 60 is 
and the cos of 60 is 1/2. Both the sin and cos of 45 is 
. So your formula is filled in like this: 
. When you do the multiplication on those sets of parenthesis, you get 
. When you add those your solution is 
. Depending upon your instructor you may have to rationalize that denominator to get that radical out from under there, but if not, that's pretty much it!
Is anyone knows the answer? Thanks. What line has a slope of 0 and goes through (5, -8)
1 answer:
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