Equation for Plane through (-5, 1, 2) Perpendicular to n = 3 i - 5 j + 2 k

  • Thread starter Thread starter Square1
  • Start date Start date
  • Tags Tags
    Planes
Click For Summary

Homework Help Overview

The discussion revolves around finding the equation of a plane that passes through the point (-5, 1, 2) and is perpendicular to the normal vector n = 3i - 5j + 2k. Participants express confusion regarding the formulation of the plane's equation and the signs used in the expression.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the equation of the plane and question the reasoning behind the signs and order in the equation provided. There is also a mention of a formula related to the dot product and its equivalence to the plane's equation.

Discussion Status

The discussion includes attempts to clarify the formulation of the plane's equation and addresses misunderstandings about the notation used. Some participants have acknowledged their confusion and have shared insights into their thought processes.

Contextual Notes

There is mention of difficulty in reading formulas and a note about the timing of homework completion affecting understanding. Participants are navigating through the notation and terminology used in the problem.

Square1
Messages
143
Reaction score
1
Find an equation for the plane through
(−5, 1, 2) and perpendicular to n = 3 i − 5 j + 2 k.



They say that :
The plane has an equation
3(x + 5) − 5(y − 1) + 2(z − 2) = 0

What confuses me is why they switched the add/subtract signs and the order of everything when in my notes they tell us the following:

vector P'knot'·P = (x − x'knot', y − y'knot', z − z'knot').
Thus, n ·P'knot'·P = 0 is equivalent to a(x − x'knot') + b(y − y'knot') + c(z − z'knot') = 0


Thanks in advance
 
Physics news on Phys.org
Hi Square! :smile:
Square1 said:
Find an equation for the plane through
(−5, 1, 2) and perpendicular to n = 3 i − 5 j + 2 k.



They say that :
The plane has an equation
3(x + 5) − 5(y − 1) + 2(z − 2) = 0

Never mind the formula (which btw i can't read :redface:) …

isn't it obvious that the LHS will be zero if x = -5, y = 1, z = 2, and not for the "minus" values? :wink:
 
P0 sounds like P "knot" but it's really P "nought". A knot is formed by joining two pieces of rope; nought means "nothing" or "zero".

You can make subscripts and exponents by clicking Go Advanced, which opens the advanced menu across the top of the input window. Use the X2 button to make exponents, and use the X2 to make subscripts.
 
Yes tim, yes mark and thanks mark. :)

Ok I got it though I misread the question. Lesson learned - don't do homework at stupid hours.
 

Similar threads

Replies
1
Views
2K
Replies
2
Views
2K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 5 ·
Replies
5
Views
1K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 15 ·
Replies
15
Views
5K
Replies
3
Views
2K
Replies
3
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K