# Write an equation that is perpendicular and passes through a point

Slopes of parallel and perpendicular lines Video transcript We're asked what is the equation of line B? And they tell us that line A has an equation y is equal to 2x plus And they say that the line B contains the point 6, negative 7. Independently Descartes used his method of normals based on the observation that the radius of a circle is always normal to the circle itself.

Roberval discovered a general method of drawing tangents, by considering a curve as described by a moving point whose motion is the resultant of several simpler motions.

An definition of a tangent was "a right line which touches a curve, but which when produced, does not cut it". It has been dismissed and the modern definitions are equivalent to those of Leibniz who defined the tangent line as the line through a pair of infinitely close points on the curve.

Tangent line to a curve[ edit ] A tangent, a chordand a secant to a circle The intuitive notion that a tangent line "touches" a curve can be made more explicit by considering the sequence of straight lines secant lines passing through two points, A and B, those that lie on the function curve.

The tangent at A is the limit when point B approximates or tends to A. The existence and uniqueness of the tangent line depends on a certain type of mathematical smoothness, known as "differentiability. At most points, the tangent touches the curve without crossing it though it may, when continued, cross the curve at other places away from the point of tangent. A point where the tangent at this point crosses the curve is called an inflection point. Circlesparabolashyperbolas and ellipses do not have any inflection point, but more complicated curves do have, like the graph of a cubic functionwhich has exactly one inflection point, or a sinusoid, which has two inflection points per each period of the sine.

Conversely, it may happen that the curve lies entirely on one side of a straight line passing through a point on it, and yet this straight line is not a tangent line. This is the case, for example, for a line passing through the vertex of a triangle and not intersecting it otherwise—where the tangent line does not exist for the reasons explained above. In convex geometrysuch lines are called supporting lines. At each point, the moving line is always tangent to the curve.

Its slope is the derivative ; green marks positive derivative, red marks negative derivative and black marks zero derivative. Analytical approach[ edit ] The geometrical idea of the tangent line as the limit of secant lines serves as the motivation for analytical methods that are used to find tangent lines explicitly.

The question of finding the tangent line to a graph, or the tangent line problem, was one of the central questions leading to the development of calculus in the 17th century. The slope of the secant line passing through p and q is equal to the difference quotient f.A starship is not an independent entity—no more than a jet plane is independent just because it can leave the ground.

Imagine for a moment, a fully loaded jet airliner flying from Los Angeles to New York. This is called the slope-intercept form because "m" is the slope and "b" gives the y-intercept. (For a review of how this equation is used for graphing, look at slope and graphing.).

I . Write the equation for a line that is a parallel or perpendicular to a line given in slope-intercept form and goes through a specific point. by changing parameters a, b and c. The properties of the graph such as slope and x and y intercepts are also explored.

The investigation is carried out by changing the coefficients a, b, and c and analyzing their effects on the properties of the graph.

We'll write the equation of the line that passes through a given point and it makes an angle with the axis of X. (y - y1) = m (x - x1) We know that m = tan a, where a is the angle made by the line.

After completing this tutorial, you should be able to: Find the slope given a graph, two points or an equation.

Write a linear equation in slope/intercept form.

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