SOLUTION: The exact value of 6cos(-61pi/6)-2sin(13pi/4) is... A. 3squaroot(3)+squaroot(2) B. -3+squaroot(2) C. -3-squaroot(2) D. 3squaroot(3)-squaroot(2)

Algebra ->  Trigonometry-basics -> SOLUTION: The exact value of 6cos(-61pi/6)-2sin(13pi/4) is... A. 3squaroot(3)+squaroot(2) B. -3+squaroot(2) C. -3-squaroot(2) D. 3squaroot(3)-squaroot(2)      Log On


   

Question 545976: The exact value of 6cos(-61pi/6)-2sin(13pi/4) is...
A. 3squaroot(3)+squaroot(2)
B. -3+squaroot(2)
C. -3-squaroot(2)
D. 3squaroot(3)-squaroot(2)
Answer by lwsshak3(11628) About Me  (Show Source):
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The exact value of 6cos(-61pi/6)-2sin(13pi/4) is...
A. 3squaroot(3)+squaroot(2)
B. -3+squaroot(2)
C. -3-squaroot(2)
D. 3squaroot(3)-squaroot(2)
**
For(-61π/6), use reference angle(-π/6) in quadrant IV where cos>0
6cos(-61π/6)=6cos(-π/6)=6√3/2=3√3
..
For(13π/4), use reference angle(5π/4) in quadrant III where sin<0
2sin(13pi/4)=2sin(5π/4)=2√2/2=√2
..
6cos(-61pi/6)-2sin(13pi/4)=3√3-√2 (ans. D)