SOLUTION: Find the exact value of the given expression (using half-angle or double-angle identities) sin15°cos15°

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Question 1160122: Find the exact value of the given expression (using half-angle or double-angle identities)
sin15°cos15°
Found 2 solutions by MathLover1, MathTherapy:
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

using Half-Angle Identities
sin%28x%2F2%29+=++sqrt%28%281+-+cos%28x%29%29%2F2%29
sin%2830%2F2%29+=++sqrt%28%281+-+cos%2830%29%29%2F2%29...... sin%2830%29=1%2F2
sin%2815%29+=++sqrt%28%281+-+sqrt%283%29%2F2%29%2F2%29
sin%2815%29+=+%281%2F4%29%28sqrt%286%29+-+sqrt%282%29%29

cos%28x%2F+2%29=+sqrt%28%281%2Bcos%28x%29%29%2F2%29
cos%2815%29=sqrt%28%281%2Bcos%2830%29%29%2F2%29.......cos%2830%29=+sqrt%283%29%2F2
cos%2815%29=+sqrt%28%281%2Bsqrt%283%29%2F2%29%2F2%29
cos%2815%29=%281%2F4%29%28sqrt%282%29+%2B+sqrt%286%29%29

}
sin%2815%29cos%2815%29=%281%2F16%29%28%28sqrt%286%29%29%5E2+-+%28sqrt%282%29%29%5E2%29}
sin%2815%29cos%2815%29=%281%2F16%29%286+-+2%29}
sin%2815%29cos%2815%29=%281%2F16%29%284%29}
sin%2815%29cos%2815%29=%281%2Fcross%2816%294%29%28cross%284%29%29}
sin%2815%29cos%2815%29=1%2F4


Answer by MathTherapy(10555) About Me  (Show Source):
You can put this solution on YOUR website!
Find the exact value of the given expression (using half-angle or double-angle identities)
sin15°cos15°
This is so, so SIMPLE! Unless of course, you prefer TORTURE, then you can go with the other person!

Use the IDENTITY: matrix%281%2C3%2C+sin+%28A%29+cos+%28A%29%2C+%22=%22%2C+%281%2F2%29+%2A+sin+%282+%2A+A%29%29