Recent content by franceboy

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    Geometry Problem - Sum of distances

    Homework Statement ABC is a triangle with I as the centre of the incircle and K as the centre of the circumcircle (I ≠ K). d(X) is the sum of the distances from a point X inside the triangle to the three sides. Verify if d(P)=d(Q) (P and Q are points inside the triangle), the lines PQ and IK...
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    Geometrical Proof: Prove Intersection Point on Line CM

    Sorry thai i did not add a sketch but a GeoGebra sketch was not accepted as file. Joffan your sketch is correct. I used the symmetry so that I " only" need to proof BX / XC * CY / YA = 1 I determined all the angles and I found some similarities but they did not help to solve the problem. Is...
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    Geometrical Proof: Prove Intersection Point on Line CM

    Homework Statement Consider an triangle ABC with M as the middle point of the side AB. On the straight line through AB you put the angle ∠ ACM at A and the angle ∠ MCB at B. Now you have two new lines. The new lines should be on the same side of AB as C. Proof that the intersection point of the...
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    Calculating Velocity and Distance for Ascending Double Cone on Rails

    Since z takes on it`s maximal value, z`(x)=0. z(x)=root((R-tan(a/2)*(tan(b/2)*x+tan(b/2)*d))2 - x2) I can solve the first equation with my calculator. Then I got the real x-value which differs from the x value of the center of mass. What is the next step?
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    Where is the image formed when a lens is placed next to an aquarium?

    My textbook covers only the lensmaker equation. With this equation I can calculate R1. But it does not tell us how to deal with the case of a lens between water and air. Is my solution for a) right?
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    Calculating Velocity and Distance for Ascending Double Cone on Rails

    Thank you. The function for the left rail is y=tan(b/2)*x+tan(b/2)*d . Then we have the equations x2+z2=r(y)2 The conclusion would be x2+z2=(R-tan(a/2)*(tan(b/2)*x+tan(b/2)*d))2 I think z can be expressed by z(x)=tan(y)*x+tan(y)*d. Back to the exercise: How I find out where the rail touches the...
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    Where is the image formed when a lens is placed next to an aquarium?

    Using sin a=tan a, I got xi= -f*xo/(f*nwater-xo). With this equation I could solve the tasks a) and b). However I was not able to solve c) because in a) we can say that the parallel ray crosses the axis in (f,0) but now this can not be said. I think the function g(x) has the same equation...
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    Calculating Velocity and Distance for Ascending Double Cone on Rails

    I was not able to find the equation for the intersection. Could you name this equation? And what should I do after solving this equation?
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    Calculating Velocity and Distance for Ascending Double Cone on Rails

    Thanks. Are my next attempts right? How do I solve this task?
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    Calculating Velocity and Distance for Ascending Double Cone on Rails

    Okay y(x) is supposed to be y(x)=tan(b/2)*x And y(x)=ycircle Then we would have the equation: (R-tan(a/2)*tan(b/2)*x)2=x2+z2 And z= root((R-tan(a/2)*tan(b/2)*x)2-x2)
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    Where is the image formed when a lens is placed next to an aquarium?

    Homework Statement There is a small shiny object in a big aquarium, which is formed like a cuboid and filled with water. The plan site of a plano-convex lens with a focal length f is put on the wall of the aquarium from outside. The object is located on the optical axis of the lens. The...
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    Calculating Velocity and Distance for Ascending Double Cone on Rails

    Sorry for answering so late. Okay we imagine that the CM is the point CM=(xCM, 0 , R+xCM*(tan(y)-tan(b/2)*tan(a/2)). Then the varying is dependent from the value of y. We can say: r=R-tan(a/2)*ycircle The centre of the circle is (xCM , ycircle , R+xCM*(tan(y)-tan(b/2)*tan(a/2)). The circle is...
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    Calculating Velocity and Distance for Ascending Double Cone on Rails

    I failed at describing the double cone with vectors and finding an intersection equation. Could you help me?
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