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In graph a, at t equals 0, the x axis displays the values from 0 to start fraction 3 lambda over 2 end fraction, and the y axis displays the values from negative A to A. The sinusoidal wave starts from (0, A), and passes through (start fraction lambda over 4 end fraction, 0), (start fraction lambda over 2 end fraction, negative A), (lambda, A), (start fraction 5 lambda over 4 end fraction, 0), (start fraction 3 lambda over 2 end fraction, negative A). A point P is labeled on (lambda, A).

In graph b, at t equals start fraction upper T over 4 end fraction, the x axis displays the values from 0 to start fraction 3 lambda over 2 end fraction, and the y axis displays the values from negative A to A. The sinusoidal wave starts from (0, 0), passes through (start fraction lambda over 2 end fraction, 0), (start fraction 3 lambda over 4 end fraction, negative A), (lambda, 0), (start fraction 5 lambda over 4 end fraction, A), (start fraction 3 lambda over 2 end fraction, 0). A point P is labeled on (start fraction 5 lambda over 4 end fraction, A).

In graph c, at t equals start fraction T over 2 end fraction, the x axis displays the values from 0 to start fraction 3 lambda over 2 end fraction, and the y axis displays the values from negative A to A. The sinusoidal wave starts from (0, negative A) and passes through (start fraction lambda over 2 end fraction, A), (start fraction 3 lambda over 4 end fraction, 0), (lambda, negative A), and (start fraction 3 lambda over 2 end fraction, A). A point P is labeled on (start fraction 3 lambda over 2 end fraction, A).

A dashed slant line joins the point P in all the three graphs and another dashed slant line joins (start fraction lambda over 2, negative A) on graph a, (start fraction 3 lambda over 4 end fraction, negative A) on graph b and (lambda, negative A) on graph c.

All values are estimated.