# line

1. ### Equation of a Line passes through.

Hi all, Iâ€™m taking a Pre-Cal and I have totally forgotten this Algebra stuff:(. Have looked everywhere, but still my work is wrong:furious:. The question ask to look for the perpendicular line (in Slope-Intercept) that pass through (1,-9) with the equation y=(4-x)/3. The correct answer is...
2. ### Fitting line to data

I want to fit two lines to the data in the attached image; one line from the top and one line from the bottom. Like what you see in the attachment. What is the best way to do this? Is there any software that can do this? thank you for your attention
3. ### Calculate third point of triangle given angle and line length

I have a triangle with the three points named A, B and C. I know the coordinates of A and B and need to calculate C. I also know the angle a and that |AB|=|AC|. Unfortunately the only formulas for triangles I remember, are about calculating an unknown length or angle, and I need the coordinates...
4. ### Calculating endpoint of 3D line with start point and angle.

So I need to calculate the start point (x1, y1, z1) of a 3D line of which I know the end point (x2, y2, z2), the angle which is 45 degrees, but where I also know y1. I furthermore know that y1<y2. So is there a simplified formula for this, given the additional info?
5. ### Circumference and secant line

How to get the radius Ï of the circumference as a function of the angle Î¸ formed between the secant line r and the origin O? The center of the circumference is given by the ordered pair (Î±, Î²), and b and a are the projections on the x and y axis, respectively, from the point P where line r...
6. ### Check my understanding (line integrals)

Ok so if I'm understanding correctly, line integrals integrate over a curve (C) unlike over a region on the x or y axis like a regular integral would. So you have a curve represented by the vector function r(t) = C = x(t) i + y(t) j let's take a region along that curve that can be defined by...
7. ### Projecting points on a line - 2D

a = (1, 0) b = (1, 1) c = (0, 1) L: x + y = 4/3 Proj_{L}(a) = ? \\ Proj_{L}(b) = ? \\ Proj_{L}(c) = ? \\ 1. How do I express x + y = 4/3 in matrix form for projection matrix multiplication? 2. Is it possible to calculate the projection{a,b,c} on L with matrix multiplication?
8. ### how to draw a non-terminating decimal on a number line

Hi, it is possible to draw 3.456 on a number line and graph it, but how is it possible to draw the following non-terminating decimals, i.e 2.3460274501837330986734345672095867, pi, 4.265686866868686868686868, on a number line and graph? Thanks.
9. ### Find ellipse sector line length?

So if I know a and b of the ellipse and also the angle of it. How can I calculate the curved line from the point of b to the point of a? I want the length of the curved line. For example: In a circle you can calculate the circle sector by knowing the angle and the radius.. If possible using...
10. ### Line, Surface, and Volume elements- Parameters

Line, Surface, and Volume elements. Let r be a vector in space r=(x,y,z) LINE x,y,z given in terms of parameter u. dr=r'du. dL=|r'|du SURFACE x,y,z given in terms of parameters u,v. In any coordinate direction, holding the other fixed, dr=r_{u}du, dr=r_{v}dv. dA=|r_{u}Xr_{v}|dudv...
11. ### equation of a tangent line

Compute an equation of the tangent line to the curve q(s) = (s,sin(Ï€s^2),cos(3Ï€s^2))at the point (2,0,1) where sâˆˆR in this questions my steps will be these: step1: match x,y,z components of the point and q(s) to find parameter s step2: find q'(s) step3: insert parameter...
12. ### Tangent Line

Let me explain my steps for the attached question and please someone confirm me. Compute a unit vector that lies tangent to the curve at the given point. Hint:If you are given a point, you need to first find the t value that produces that point. (a)r(t) =(3...
13. ### Trying to solve the angle of a line tangent on a circle

I've attached the image and I am trying to solve angle "A" of a line that's tangent to a circle. Thanks for your help.
14. ### Equation of a line

Help!!! I need a mathematician to solve this... The line 5x+Ky-15=0 is perpendicular to the line 2x+5y-3=0,find the value of K.
15. ### Minimal value of the sum of two line segments

I proved that AF + EF \geqslant \frac{a \sqrt{12}}{3}. It's the case when AF \geqslant \frac{AC}{2}, and EF \geqslant \frac{a}{3\sqrt{2}} (when EF \perp BD). Do you know how to prove the original inequality?
16. ### Proof that two line segments are equal

So far, I've done this (see picture). From OP=OQ comes out that the triangle OPQ is isosceles triangle. This means that \measuredangle OPQ = \measuredangle OQP. Now, \measuredangle AQP = \measuredangle AQO + \measuredangle OQP = 90$/degree$ + \measuredangle OQP and \measuredangle DPQ =...
17. ### [ASK] Reflection of a Line by Another Line

The reflection of the line 5x - 7y - 13 = 0 by the line y = -x is .... A. 7x + 5y - 13 = 0 B. 7x + 5y + 13 = 0 C. 7x - 5y - 13 = 0 D. 7x - 5y + 13 = 0 E. 7y + 5x + 13 = 0 This one I totally have no idea. Like, at all.
18. ### [ASK] Line of a Mirror

The point B(3, -1) is reflected by the line g and results in B'(5, 7). The equation of line g is .... A. 4y + x - 15 = 0 B. 4y + x - 9 = 0 C. 4y + x + 15 = 0 D. 4y - x - 15 = 0 E. 4y - x - 9 = 0 Since I didn't know how to approach the problem in a formal, textbook way, I tried to get...
19. ### Condition for straight line preservation

We have not affine transform but rational transform: x' = (a \cdot x + b \cdot y +c)/(1+d \cdot x + e \cdot y) y' = (f \cdot x + g \cdot y +h)/(1+i \cdot x + j \cdot y) To find coefficients, it need 5 points and 10 nonlinear equations. But better would be only 4 (or even 3) points with...
20. ### Contour line integral question

By rewriting the integral as a contour integral around the unit circle C(0, 1) show that $\int_{0}^{2\pi}\frac{1}{2+isin(\theta)}d\theta=2pi/\sqrt{5}$