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The answer is 1/2.

2007-04-20 15:40:49 · 2 answers · asked by Adrianne G. 2 in Science & Mathematics Mathematics

2 answers

Remember that sin (x + y) = sin x cos y + cos x sin y.

So, if we take x = 70 and y = 80, we get

sin (70 + 80) = sin 70 cos 80 + cos 70 sin 80.

So we just have to find the sine of 150 degrees; this is 1/2.

2007-04-20 15:46:06 · answer #1 · answered by Anonymous · 0 0

That's the same as sin(70+80)
because
sin(70+80) = sin 70 cos 80 + cos 70 sin 80.
But sin(70+80)= sin(150) = sin(30) = ½.

2007-04-20 22:45:25 · answer #2 · answered by steiner1745 7 · 0 0

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