The polar curve is .

Graph the curves .

Observe the graph,

The maximum value of - coordinate is approximately .

Relation between polar and cartesian coordinates is .

Substitute in .

Differentiate on each side with respect to .

For maximum value, equate to zero.

Thus, critical points are .

As cosine function range is .

Find the values of the function at the extreme and critical points.

.

Thus, from the above results - coordinate of the highest points on the curve is .

Thus, from the above results - coordinate of the highest points on the curve is .