Saturday, November 19, 2011

What is the unit vector parallel to u, but running in the opposite direction?

(each 'u' should have an arrow above it)





If u=(4,2,-2), what is the unit vector parallel to u but running in the opposite direction? Express your answer in algebraic form.











How do you solve this?|||the magnitude of u is sqrt of( u dot u). The unit vector of u is u / mag of u





so mag. of u = sqrt(4^2 + 2^2 +(-2)^2 ) = sqrt(16 +4 + 4) = sqrt(24) =


2 sqrt(6)


unit vector u = (2/sqrt(6), 1/sqrt(6) , -1/sqrt(6)





the unit vector in the opposite direction is - this vector or


(-2/sqrt(6), -1/sqrt(6), 1/sqrt(6))|||(1/sqrt6)(-2, -1,1)

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