A vector r vector has magnitude 14 and direction ratios 2,3,-6 .Find the directino cosines and components of r vector ,given that r vector makes an acute angle with x-axis.

Given, a vector r has magnitude 14 and direction ratios are 2,3,-6. So, r=14Let l,m,n are the direction cosines of r. Since r makes an acute angle with x-axis, so,  l>0Direction ratios of  are 2,3,-6, so,Direction cosinesl,m,n of r=222+32+-62,322+32+-62,-622+32+-62                                                =249,349,-649                                                =27,37,-67Thus,Direction cosines of rare l=27,m=37, and n=-67Also,r=rli+mj+nk=1427i+37j-67k=4i+6j-12kHence, components of r along x-axis, y-axis and z-axis are 4i,6j, and -12k respectively.

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