Math Problem Statement

En linje l går gennem punktet P(4,7) og har hældningsvinklen v = 30°. a) Bestem en ligning for l.

Solution

To find the equation of a line ll passing through the point P(4,7)P(4,7) with an inclination angle v=30v = 30^\circ, we can use the following approach:

  1. Calculate the slope mm using the inclination angle: The slope of a line with an inclination angle vv is given by: m=tan(v)m = \tan(v) Given v=30v = 30^\circ, we find: m=tan(30)=130.577m = \tan(30^\circ) = \frac{1}{\sqrt{3}} \approx 0.577

  2. Form the equation of the line: The equation of a line in point-slope form is: yy1=m(xx1)y - y_1 = m(x - x_1) Substituting P(4,7)P(4,7) as (x1,y1)(x_1, y_1) and m=13m = \frac{1}{\sqrt{3}}, we get: y7=13(x4)y - 7 = \frac{1}{\sqrt{3}} (x - 4)

  3. Simplify the equation (optional): Expanding and simplifying the equation: y=13x43+7y = \frac{1}{\sqrt{3}} x - \frac{4}{\sqrt{3}} + 7 Or, in a more approximate form: y0.577x+4.31y \approx 0.577 x + 4.31

Thus, the equation of the line ll is: y=13x+4.31y = \frac{1}{\sqrt{3}} x + 4.31

Would you like a deeper explanation or more details on this solution?

Here are some related questions you might explore:

  1. How would the equation change if the inclination angle was different?
  2. What is the effect of using a different point on the line to form the equation?
  3. How do we interpret the y-intercept of this line?
  4. How can we confirm if another point lies on this line?
  5. What would the line equation be in a different form, such as the general form Ax+By+C=0Ax + By + C = 0?

Tip: The slope of a line directly depends on the angle it makes with the positive x-axis; this is particularly useful for visualizing lines in geometry.

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Math Problem Analysis

Mathematical Concepts

Analytic Geometry
Linear Equations
Inclination Angle

Formulas

Slope formula m = tan(v)
Point-slope form y - y1 = m(x - x1)

Theorems

Tangent of an Angle for Slope Calculation

Suitable Grade Level

Grades 10-12