The angle of inclination of the line (where is a parameter) is ( ).
A: 30°
B: 60°
C: 90°
D: 135°
The angle of inclination of the line (where is a parameter) is ( ).
A: 30°
B: 60°
C: 90°
D: 135°
Given the parametric equations of the line:
\begin{cases}
x=-2+t\cos(\text{30°}) \\
y=3-t\sin(\text{60°})
\end{cases}
To find the angle of inclination of the line, we need to determine its slope (). From the parametric equations, we obtain the change in and with respect to the parameter :
\begin{align*}
\Delta x &= \cos(\text{30°}) \\
\Delta y &= -\sin(\text{60°})
\end{align*}
Therefore, the slope of the line is the ratio of to :
\begin{align*}
m &= \frac{\Delta y}{\Delta x} \\
m &= \frac{-\sin(\text{60°})}{\cos(\text{30°})} \\
m &= \frac{-\sqrt{3}/2}{\sqrt{3}/2} \\
m &= -1
\end{align*}
The slope of the line is equal to the tangent of its angle of inclination with the positive direction of the x-axis, thus:
To find the angle that corresponds to , we can consider angles in the second quadrant where the tangent is negative, and we know that .
Therefore, we conclude that the angle of inclination of the line is .