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## anonymous 4 years ago OK gonna need some help... Don't remember this! Find sin 540° + 4(tan150°)(cot120°)

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1. anonymous

sin 540 = sin 180 = 0 tan 150 = -1 / sqrt(3) cot 120 = -1 / sqrt(3)

2. anonymous

$0 + 4 \times ( {-1 \over \sqrt{3}} \times {-1 \over \sqrt{3}} )$ $4 \times { { -1 \times -1 } \over \sqrt3 \times \sqrt3 }$ $4 \times { 1 \over 3 } = { 4 \over 3}$

3. anonymous

Is that how you do it? crazy I would have never got that in a million years.

4. anonymous

Simple, i calculate the results for the 3 different goniometric expressions, then feed them into the given formula. Remember, with math, it's not enough to remember something only for a test. You'll need everything you learn in subsequent tests.

5. anonymous

thought tan = 150 would be 30 degrees which is sqrt(3)/3 and cot = 120 would be 60 degrees which is sqrt(3)/3

6. anonymous

wouldn't they both be negative as well?

7. anonymous

yep, they are, but a negative times a negative is a positive

8. anonymous

since sqrt(3)/3 x sqrt(3)/3 = 3/9 and 0 + 4(3/9) = 7/9? So it would be 7/9

9. Mertsj

$\frac{4}{1}\times\frac{3}{9}=\frac{12}{9}=\frac{4}{3}$

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