Finding Angle Between Lines Passing Through Points (-2,-1) and (4,1)

In summary, the conversation discusses finding the equation of a straight line passing through the point (2,3) and inclined at 30 degrees to the positive direction of the x-axis. The conversation involves using the gradient of the line and a point on the line to find the equation. The final equation is y = 0.58x + 1.85.
  • #1
cherrypie
3
0

Homework Statement



Find the equation of a straight line which passes through the point (2,3) and is inclined at 30 Celsius to the positive direction of the x-axis.

The Attempt at a Solution


i have no idea how to to this question as i was away for a week of school >< and my teacher gave my catch up worksheets. I am falling behind class. so need help

Homework Statement


find the angle between the straight line 3x-2y=4 and the line joining the points (-2,-1) and (4,1)

please guide me step by step

thanks
 
Physics news on Phys.org
  • #2
What you need for the first one is a point on the line (which you were given) and the gradient.
This will help you to get the gradient:

Tan(angle the line makes with the +ve x-axis)=gradient of the line.

EDIT: I think you mean 30 degrees and not celsius as that implies a temperature.
 
Last edited:
  • #3
rock.freak667 said:
What you need for the first one is a point on the line (which you were given) and the gradient.
This will help you to get the gradient:

Tan(angle the line makes with the +ve x-axis)=gradient of the line.

EDIT: I think you mean 30 degrees and not celsius as that implies a temperature.

so y=mx+c
Tan(30degrees) is m =0.56
so y=0.56x+c

find c, sub (2,3)

y=0.56x+1.85 ?
 
  • #4
(0.56)(2)+ 1.85= 1.12+ 1.85= 2.97, not 3. Did you mean tan(30)= 0.58?
 

1. What is the formula for finding the angle between two lines passing through given points?

The formula for finding the angle between two lines passing through points (x1,y1) and (x2,y2) is given by arctan((m2-m1)/(1+m1*m2)), where m1 and m2 are the slopes of the two lines.

2. Can the angle between two lines passing through given points be negative?

No, the angle between two lines is always positive. If the result obtained from the formula is negative, it is usually converted to its positive equivalent by adding 180 degrees.

3. How do I find the slope of a line passing through a given point?

The slope of a line passing through a given point (x1,y1) is given by the formula m = (y2-y1)/(x2-x1), where (x2,y2) is any other point on the line.

4. Can I find the angle between two vertical lines passing through given points?

No, the formula for finding the angle between two lines is only applicable for non-vertical lines. For vertical lines, the angle between them is always 90 degrees.

5. Is there a simpler way to find the angle between two lines than using the formula?

Yes, you can use a graphing calculator or online tool to plot the lines and find the angle between them visually.

Similar threads

  • Precalculus Mathematics Homework Help
Replies
1
Views
526
  • Precalculus Mathematics Homework Help
Replies
2
Views
1K
  • Precalculus Mathematics Homework Help
Replies
11
Views
2K
  • Precalculus Mathematics Homework Help
Replies
6
Views
2K
  • Precalculus Mathematics Homework Help
Replies
2
Views
1K
  • Precalculus Mathematics Homework Help
Replies
3
Views
2K
  • Precalculus Mathematics Homework Help
Replies
6
Views
2K
  • Precalculus Mathematics Homework Help
Replies
6
Views
1K
  • Precalculus Mathematics Homework Help
Replies
11
Views
2K
  • Precalculus Mathematics Homework Help
Replies
2
Views
2K
Back
Top