Test 1: 11.1 to 12.3 Flashcards
How do you find a unit vector?
v / ||v|| or 1 / ||v|| * v
How do you find the X and Y components of any nonzero vector v making an angle theta with the positive x axis?
||v|| or ||v|| cos theta*i + ||v|| sin theta * j
What is the standard equation of a sphere?
(x-x0)^2 + (y-y0)^2 + (z-z0)^2 = r^2
What is the midpoint formula in 3 dimensions/
(x1 + x2)/2, (y1+y2)/2, (z1+z2)/2
How do you know vectors are parallel?
If there is some scalar c such that u = cv
How do you find the dot product?
u1v1 + u2v2+ u3v3
How do you find the angle between two nonzero vectors u and v?
cos theta = u dot v / ||u|| ||v||
How do you determine if two vectors are orthogonal?
Their dot product is 0
How do you find the 3 angles between a nonzero vector and the three unit vectors i j k?
Use directions cosines cos alpha = v1 / ||v||, cos beta = v2 / ||v||, cos gamma = v3 / ||v||
What is the sum of the squares of the direction cosines?
1
What is the formula for projection of u onto v using the dot product(
Both vectors must be nonzero. projv^u = ( u dot v / ||v||^2) * v
What is the cross product of two vectors?
(u2v3 - u3v2)i - (u1v3 - u3v1)j + (u1v2 - u2v1)k
How do you get a vector orthogonal to two other vectors?
Use the cross product.
What’s a way to find the angle between u and v using the cross product?
|| u x v || = ||u|| ||v|| sin theta
What does it mean if u x v is 0?
u and v are scalar multiples of each other
What is the area of a parallelogram having u and v as adjacent sides?
|| u x v ||
What is the triple scalar product?
u dot (v x w)
How do you find the volume V of a parallelepiped with vectors u v and w as adjacent edges?
Take the absolute value of the triple scalar product
In the parametric equation x = x1 + at, which piece is the direction vector?
a