54 Minutes ago: 19 June 2011 17: 07 Hey, I'm struggling with a few questions in the book of Heinemann P6, it seems not to explain the method and I can find it out:

Ex. 4 c question 10:

Find an equation of the level in the form: r.n = p

It is a point in the plane a = I + 4 k and a line in the plane-R = t (2i + 3j k)

Now I think I am on the search to n' work, that r.n = 0, but I'm not really sure how you start, or how one use the point in the calculation. Help will be appreciated!

48 Minutes ago: 19 June 2011 17: 13 Hey, I'm struggling with a few questions in the book of Heinemann P6, it seems not to explain the method and I can find it out:

Ex. 4 c question 10:

Find an equation of the level in the form: r.n = p

It is a point in the plane a = I + 4 k and a line in the plane-R = t (2i + 3j k)

Now I think I am on the search to n' work, that r.n = 0, but I'm not really sure how you start, or how one use the point in the calculation. Help will be appreciated!

r.n shows 0 = you, what? You are perpendicular. So you need a vertical vector in the i + k and 2i + 3j-k... 37 Minutes ago: 19 June 2011 17: 24 Thanks for the quick responses!

So, I take only the cross product of (2i + 3j k) and (i + 4 k)? Seems not to me, I am the answer for which is n = (4i - 3j k)?

EDIT: Yes it is I just needed to take a factor of 3 by the result. Duh!

Last edited by dam; 35 Minutes ago at 17: 26.

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