MHB What is the Angle Between Vectors Using the Dot Product Formula?

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To find the angle between the vectors v = -5√3i + 5j and w = 5i using the dot product formula, the equation cos(θ) = (v · w) / (|v| |w|) is applied. The dot product of the vectors is calculated as v · w = (-5√3)(5) + (5)(0) = -25√3. The magnitudes of the vectors are |v| = √((-5√3)² + 5²) and |w| = 5. By substituting these values into the formula, the angle θ can be determined.
brinlin
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Find the angle between the vectors $$v=-5\sqrt{3}i+5j$$ and $$w=5i$$
 
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I'd use the dot product formula ...

$\cos{\theta} = \dfrac{\vec{v} \cdot \vec{w}}{|v| \, |w|}$
 
when we use the dot product formula. What would we plug in for v and w.
 
to calculate the dot product of two vectors given in component form …

$(a \vec{i} + b \vec{j}) \cdot (c \vec{i} + d \vec{j}) = ac + bd$

… note the dot product is a scalar quantity
 
brinlin said:
when we use the dot product formula. What would we plug in for v and w.
? YOU said, in your first post that
$v= -5\sqrt{3}i+ 5j$
$w= 5i$.
 
Here is a little puzzle from the book 100 Geometric Games by Pierre Berloquin. The side of a small square is one meter long and the side of a larger square one and a half meters long. One vertex of the large square is at the center of the small square. The side of the large square cuts two sides of the small square into one- third parts and two-thirds parts. What is the area where the squares overlap?

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