Ok, ive got a question. Its probably something really stupid that im overlooking, but ill ask anyway. Say i have the question: if a plane is can travel 75 m/s north (75j i assume?) under normal conditions, what velocity will the pilot need to set if he is to travel directly north when there are winds of 21i+8j m/s blowing. Since i need to find the velocity which will make the plane travel at 75m/s north, 75j is therefore the resultant. If ai+bj is the velocity the pilot needs to set his engines at, i can say: 75j=ai+bj+21i+8j I then equate the components, to get: i 0=a+21 j 75=b+8 From that, i can solve for a and say that a=-21, and if i then substitute that into the equation: [tex]75^2=(-21)^2+b^2[/tex] solve for b and that gives me the velocity vector -21i+72j, which is the correct answer. What im wondering is, when i equated the components, i got two equations. When i used the first equation (0=a+21) and used the value of a to find the final vector, i get the correct answer, but when i used the value from solving b from 75=b+8, i get the wrong answer. Thanks, Dan.