Comparing Line Slopes: Finding Smaller Angle Between -6 and 1/2 Slopes

Question

Two lines have slopes of 6 -6 and 12 \frac{1}{2} .

Which of the lines forms a smaller angle with the x-axis?

Video Solution

Solution Steps

00:00 Find which of the lines has a smaller angle with the X-axis
00:03 Use the formula to calculate slope based on angle with X-axis
00:07 Substitute the slope according to given data and calculate the angle
00:11 Isolate the angle
00:18 This is the angle of the first line
00:21 Find the angle of the line relative to X-axis
00:26 This is the angle relative to X-axis
00:31 Use the same method to find the angle of the second line
00:36 Substitute the slope according to given data and calculate the angle
00:40 Isolate the angle
00:45 This is the angle of the second line
00:50 And this is the solution to the question

Step-by-Step Solution

We will use the formula:

m=tanα m=\tan\alpha

Let's check the slope of minus 6:

6=tanα -6=\tan\alpha

tan1(6)=α \tan^{-1}(-6)=\alpha

80.53=α -80.53=\alpha

18080.53= 180-80.53=

99.47=α1 99.47=\alpha_1

Let's check the slope of one-half:

12=tanα \frac{1}{2}=\tan\alpha

tan1(12)=α \tan^{-1}(\frac{1}{2})=\alpha

26.56=α2 26.56=\alpha_2

\alpha_1 > \alpha_2

Answer

The line with a slope of 12 \frac{1}{2}