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Find a point on the parabola , where the tangent is parallel to the chord joining (3, 0) and (4, 1).
Here we are asked to find the coordinate of the point where the tangent is parallel to the chord joining (3, 0) and (4, 1).
To find this coordinate we need to apply Lagrange's mean value theorem for the function in the interval [3, 4].
We know that all the polynomial functions are continuous functions.
Therefore is also a continuous function, and
, which exists for all , so is differentiable in (3,4).
Thus both the conditions of Lagrange's mean value theorem are satisfied.
So, there must exist a point such that 
Now 
Therefore,  
, which belongs to (3, 4).
Thus, 
So, at the point on the given curve the tangent is parallel to the chord joining the points (3, 0) and (4, 1).
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