 Hello and welcome to the session. Let us understand the following question today. If x and y are connected parametrically by the equations given below, without eliminating the parameter, find dy by dx. Given to us, x is equal to a cos theta and y is equal to b cos theta. Now let us write the solution. Given that x is equal to a cos theta and y is equal to b cos theta. So dx by dx theta is equal to minus a sin theta and dy by dx theta is equal to minus b sin theta. So therefore, by chain rule, dy by dx is equal to dy by d theta multiplied by d theta by dx. Which is equal to dy by d theta is equal to minus b sin theta multiplied by d theta by dx. We have dx by d theta is equal to minus a sin theta. So d theta by dx is equal to 1 by minus a sin theta. Now we see that minus and minus gets cancelled and sin theta and sin theta gets cancelled. So we are left with b by a. Therefore, dy by dx is equal to b by a and d by a is our required answer. I hope you understood the question. Bye and have a nice day.