Hey you guys I have a midterm coming soon and I was just wondering how you guys
ID: 3374318 • Letter: H
Question
Hey you guys I have a midterm coming soon and I was just wondering how you guys would go about solving these types of problems.
For example for the first part ,dot product is basically the x and y multipled with each other and then you add them.
This is what types of questions it contains:
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Explanation / Answer
<a> . <b> = (axi+ayj+azk).(bxi+byj+bzk)
<a>x<b>=
| i j k |
| ax ay az |
| bx by bz |
unit vector
<c> =<a>/|a| unit vector in dir of <a>
<d>=<b>/|b| unit vector in dir of <b>
<e> = <a>x<b>/(|<a>x<b>|) unit vector in dir of <a>x<b>
to find equation of line
first find equation of plane
(X-ax)/b =(Y-ay)/c=(Z-az)/d
will give the equation
let any plane parallel to plane x-3y+z=-17 is
x-3y+z= d
it passes through A(2, 1, -- 3) so
2 -- 3(1) + (--3) = d Or d = -- 4
required plane is x --3y + z + 4 = 0
cos? = a.b / |a||b| to find angle betn 2 vectors
Given a plane
ax+by+cz+d=0
and a point x_0=(x_0,y_0,z_0), the normal vector to the plane is given by
v=[a; b; c],
and a vector from the plane to the point is given by
w=-[x-x_0; y-y_0; z-z_0].
Projecting w onto v gives the distance D from the point to the plane as
D = |proj_(v)w|
= (|v