find the exact value of the expression. sin25[] cos35[] +cos25[] sin35[]?

1. sqrt[]3/3
2. -sqrt[]3/2
3. 5/12
4. 1/2

2007-10-19 13:30:52 · 1 answers · asked by dilljam1977 1 in Science & Mathematics ➔ Mathematics

1 answers

Use the identity:
sin(u +/- v) = sinu cosv +/- cosu sinv
sin25 cos35 + cos25 sin35 = sin(25 + 35) = sin60 = (√3)/2
I suspect there's a misprint in choice 1. It should read (√3)/2

2007-10-19 15:15:16 · answer #1 · answered by jsardi56 7 · 0⤊ 0⤋

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