A microphone Q is attached to three pegs A, B, C by the cables. Knowing the peg
ID: 1860553 • Letter: A
Question
A microphone Q is attached to three pegs A, B, C by the cables. Knowing the peg locations, micropphone location, and the angle, theta, between the vertical walls, express Lb and Lc soley in terms of numbers and theta. And calculate Lb when theta = 120 degrees
Distance from A to B: 20 m
Distance from B to C: 15m
Distance from No to B: 8m
(No is the origin)
Q's measure from No along cable BC: 7m
Q's height above No: 5m
Q's measure from No along cable BA: 8m
La: Length of cable joining A and Q: 16.9 m
Lc: Length of cable joining C and Q: 14.2 m
position vector from No to Q = 7i + 5j +8k
La = sqrt(202-168cos(theta)
Explanation / Answer
Lb = sqrt(285 - 113cos(120)) = 18.47
Lc = sqrt(285 - 138cos(120)) = 18.81
where i got 285 from 16.9^2
n i got 113 from the sum of the coefficients of the given vecort...7^2 + 8^2 = 113
n for 138 = sum of the coefficients of the given all vecorts....7^2 + 8^2 + 5^2 = 138
nw get it...nw pls rate me...thnks
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