Scalar Triple Product Calculator
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What is Scalar Triple Product
The Scalar Triple Product is a way of multiplying three vectors to get a scalar quantity. This product represents the volume of the parallelepiped formed by the three vectors. The result is a single number, which can be positive, negative, or zero, depending on the orientation of the vectors.
Vectors in three-dimensional space can be represented as \(\vec{v} = (v_1, v_2, v_3)\), where \(v_1\), \(v_2\), and \(v_3\) are the components of the vector along the x, y, and z axes, respectively.
Steps to Calculate the Scalar Triple Product
Here are the steps to calculate the scalar triple product of three vectors:
- First, calculate the cross product of two of the vectors.
- Then, take the dot product of the resulting vector with the third vector.
- The resulting value is the scalar triple product.
Formula
The scalar triple product of vectors \(\vec{a}\), \(\vec{b}\), and \(\vec{c}\) is given by:
\[\vec{a} \cdot (\vec{b} \times \vec{c}) = \begin{vmatrix}a_1 & a_2 & a_3 \\b_1 & b_2 & b_3 \\c_1 & c_2 & c_3 \end{vmatrix}\]
Example
Let's take an example to illustrate the process. Suppose we have three vectors a, b, and c:
\(\vec{a} = (a_1, a_2, a_3)\) = (1, 2, 3)
\(\vec{b} = (b_1, b_2, b_3)\) = (4, 5, 6)
\(\vec{c} = (c_1, c_2, c_3)\) = (7, 8, 9)
To find the scalar triple product \(\vec{a} \cdot (\vec{b} \times \vec{c})\), we follow these steps:
- First, calculate the cross product \(\vec{b} \times \vec{c}\):
- Next, take the dot product of \(\vec{a}\) with the resulting vector:
\( \vec{b} \times \vec{c} = \)\( \left( b_2 c_3 - b_3 c_2, b_3 c_1 - b_1 c_3, b_1 c_2 - b_2 c_1 \right) \)
Substituting the given values:
\( \vec{b} \times \vec{c} = \)\( \left( 5 \times 9 - 6 \times 8, 6 \times 7 - 4 \times 9, 4 \times 8 - 5 \times 7 \right) = \)\( \left( 45 - 48, 42 - 36, 32 - 35 \right) = \)\( \left( -3, 6, -3 \right) \)
\( \vec{a} \cdot (\vec{b} \times \vec{c}) = \)\( a_1 (-3) + a_2 (6) + a_3 (-3) \)
Substituting the values of \(\vec{a}\):
\( \vec{a} \cdot (\vec{b} \times \vec{c}) = \)\( 1 \times (-3) + 2 \times 6 + 3 \times (-3) = \)\( -3 + 12 - 9 = 0 \)
The resulting value is 0.
Therefore, the scalar triple product of \(\vec{a} = (1, 2, 3)\), \(\vec{b} = (4, 5, 6)\), and \(\vec{c} = (7, 8, 9)\) is 0.