A Triangle with Vertices at (X1, Y1), (X2, Y2), and (X3

question 408

Multiple Choice

A triangle with vertices at (x1, y1) , (x2, y2) , and (x3, y3) has area equal to the absolute value of D, where $$D = \frac { 1 } { 2 } \left| \begin{array} { l l l } x _ { 1 } & y _ { 1 } & 1 \\x _ { 2 } & y _ { 2 } & 1 \\x _ { 3 } & y _ { 3 } & 1\end{array} \right|$$ Find the area of the triangle having vertices at P, Q, and R.
- $$\mathrm { P } ( - 3 , - 3 ) , \mathrm { Q } ( 0,0 ) , \mathrm { R } ( 5 , - 1 )$$

• A) 12
• B) 18
• C) 0
• D) 9

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Definitions:

Conditioned Stimulus

A stimulus that was once neutral but, after being paired with the unconditioned stimulus, gradually induces a conditioned response.

Aplysia

A genus of sea slugs that are often used in neurological research due to their simple, large nerve cells.

Squirt

To eject liquid in a thin, fast stream through a narrow opening.

Classical Conditioning

A learning paradigm where two stimuli are unceasingly linked; initially, the response is triggered by the second stimulus, but with time, it is triggered by the first stimulus alone.