1. M

    Exponential expansion

    I've got a cell line with a gene that gets bigger exponentially. I cultured the cells from 16/1/17 for 295 days and the gene expanded exponentially. For the second culture, cells from culture 1 frozen on 22/5/17 (d127), were thawed on 2/1/18 and cultured for 196 days. For the third culture...
  2. S

    Enumerating two circles intersect transversally at two points in a standard torus

    Hi; Let T be a standard torus in R^3. Let C_1 and C_2 be two circles in T such that C_1 and C_2 intersect transversally at two distinct points, say p and q. By transverse intersection I mean tangent intersection is not allowed. Orient C_1 and C_2 and let l_1 be an arc in C_1 from p to q...
  3. F

    A intersect (B U C)

    Define sets U, A,B and C as shown below find U={a,b,c,d,e,f,g,h} A={f,g,h} B={a,g,h} C={a,b,c,d,e} What is A'n(b U c)
  4. maxpancho

    How to find where these two functions intersect?

    $y=x \\ y=\sin(\frac{\pi x}{3}) \\ x=\sin(\frac{\pi x}{3}) $ ??
  5. E

    Two lines intersect at P, find coordinates of P?

    Hello, I am working on a set of problems. I don't quite even know where to begin. Any help would be greatly appreciated. Two lines with equations r1= (2,3,-1)+s(5,-3,2) and r2= (9,2,2)+t(-3,5,-1) intersect at the point P. Find coordinates of P.
  6. R

    In a circle of radius 25 inches, a central angle of 35° will intersect the circle for

    In a circle of radius 25 inches, a central angle of 35° will intersect the circle forming an arc of length ____. A. 1.17 feet B. 15.27 feet C. 875 inches D. 15.27 inches My Math please check if this is correct: 35° x(multiply) π/180 = 7π/36 x(multiply) 25 = answer: 15.27 But answer B. and D...
  7. I

    Determining whether the lines are parallel, intersect, or skew

    I have a problem where i don't have the solution to since i like to practice odd problems. I am not sure if i have done this correctly. Determine whether the lines L1: 1 + t, y = 2 + 3t, z = 3 + t L2: 1 + t, y = 3 + 4t, z = 4 + 2t are parallel, intersecting, or skew. If they intersect find...
  8. L

    Show that two surfaces intersect orthogonally at a point P

    I was given this question to take home and practice but we have not been shown anything like this before and there in nothing in the text like this either. If anyone has any tips on how to start this question I would really appreciate it. Two surfaces are said to intersect orthogonally at a...
  9. J

    Intersect points

    I was given this question: Find the tangent through point (1,-1) of y^2 = x^3 -2x + 2. After some time i found out that this is (x-3)/2. But the b) part of the question was: the curves intersect at another point, find this? And i couldnt because setting both equations equal to each other gives...
  10. J

    Where does the plane intersect the curve?

    Find the point(s) where the following plane and curve intersect: 2x+3y-9z=0 r(t)= <3cost, 3sint, cost> for [0,2pi]
  11. J

    Where does the plane intersect the axis?

    Find the points at which the plane 3x-4y+z=12 intersects the coordinate axis and find the equations of the lines where the plane intersects the coordinate planes.
  12. S

    Prove algebraically- the values of k that do no intersect the circle

    Hope im in the right forum post :) Basically i have to prove algebraically- the values of k in y=kx+7 that do no intersect the circle x2 +y2=25 What i already know -In my text book i learnt that the radius of the circle is sqrt 25=5 so radius all the way around the circle is 5. The line...
  13. C

    Intersect of Line and Circle

    Samatha is running near the Circular Park, the shape of a perfect circle. It has a radius of 8 cm. She begins from a point 10 cm west and 3 cm south of the center of the park. She heads toward a point 20 cm east and 4 cm north of the center of the park. Though, when she reaches a point due...
  14. K

    union and intersection of family sets

    Solved! union and intersection of family sets Hi there I'm new here, but I guess I'm going to ask many questions in the future. I'm trying to study mathematics on my own, but I need some help to make sure I'm understanding the concepts correctly... Anyways, here is my first problem. I'm...
  15. S

    tangent lines of parabola that intersect on a certain point...

    Consider the parabola y = \frac{x^2}{100} Find another point on the parabola with a tangent line that goes through (100,50). --- Can someone guide me through this please? It's due for homework tomorrow, I've got as far as figuring out the tangent line is y=2x-150. Not sure what else to...
  16. S

    Finding a point inside of a cone/cube intersect

    I am trying to solve a puzzle with a very large search space, and I think it would be most helpful if I could find points that lie within a certain region of the cube, defined by a cone. That is, the points that define the cube are: (0,0,0), (0,0,1), (0,1,0), (0,1,1), (1,0,0)...
  17. O

    Show that the two lines do not intersect.

    Hi all working through Anton and Busby.., if i have two vectors, v = (1,2,1)s and v = (9,6,0) + (0,1,-1)t how can i show that they do not intersect in 3-space ?
  18. A

    How to find where two circles intersect

    Hello If I have these two circles: (x + 1)^2 + y^2 = 25 and (x - 2)^2 + (y-1)^2 = 9 How do I work out where the circles (or if) intersect? It is difficult to set eg y= due to the different terms of x. Angus
  19. Y

    Line plane intersect within boundaries

    Hi I have managed to calculate where a line intersects a plane by substituting the parametric equations of a line into the equation of a plane. If a plane can be defined as infinite and a line must intersect the plane at some point unless paralell to the line and not colinear, how can you...
  20. oldguynewstudent

    For any quadrilateral the lines containing the diagonals always intersect

    Please let me know if the following proof is solid or if it contains errors. Thanks. Show that for any quadrilateral (convex or not), the lines containing the diagonals always intersect. (From Edwin E. Moise Elementary Geometry from and Advanced Standpoint 3rd Ed.) Proof: By Theorem 1, the...