00:01
Hello students, here we have given points that is x1, y1 and x2, y2 and the path y is equal to y of x.
00:17
Now to find the path y of x that has the shortest length that is in a straight line, we consider length of the path is equal to dx square plus dy square power 1 by 2 that is root.
00:38
Now dy is equal to dy by dx that is y dash of x into dx.
00:47
Now substituting this in the above equation, ds is equal to 1 plus y dash of x square power 1 by 2 as it is.
01:02
Here we take common as dx from both, hence we write dx because dx square power 1 by 2 is dx.
01:14
The shortest distance of the path between points 1 and 2 is given by this equation.
01:21
Now in polar coordinates, we consider x is equal to r cos theta, y is equal to r sin theta, then dx is equal to r minus sin theta d theta and dy is equal to r cos theta d theta.
01:49
Hence, we can write y dash of x is equal to dy by dx dividing r cos theta by r sin theta, rr get cancelled and we get minus cot theta because cos theta by sin theta is cot theta.
02:13
Hence we obtain the equation.
02:16
Next to calculate distance, let us consider starting from a and ending to b at t is equal to 1...