Q.If O and o' are circumcentre and orthocentre of triangle ABC , than OAvector +OBvector +OCvector equals 1. 2oo'vector 2. oo'vector 3. o'ovector 4. 2o'ovector please give your choice with correct explanation

Given two vectors A and B where A=-5i+3j-k and B=8i-3j+4k. Find 1)(A-2b).3k 2)the direction of cosines of A 3)vector projection of A on B 4)the equation of plane perpendicular to B I know how to do everything from 1 to 3 except for 4.Can someone teach me only number 4.Thanks.Pleassss

Assume that a and b are two vectors in R^3 with the property that a*x = b*x for every vector x in R^3. Must a = b? If so, prove it. If not, give a counterexample. what is this question asking?

A man walks 18.5 km west, 24.0 km at 30 degrees northwest and then 12.0 km north. Show that the order of adding the vectors does not affect the resultant (to demonstrate make two diagrams for this). What is his resultant displacement? What distance did he walk?

An electronic score board of mass 500 kg is suspended from a ceiling making an angle of 70 degrees with the ceiling.The weight is evenly distributed. Determine the tension in the cables in newtons