Osgood, William F. (William Fogg), 1864-1943, Graustein, William C. (William Caspar), 1888-1941, joint author · New York : The Macmillan Company · leaf 218
ons are unnecessary.For, the curve is symmetric in the ray$ = 90°. To prove this, Ave note that, ifP: (r, 0) is any point of the curve, thenthe point P: (r, 180°-^), which issymmetric to P in the ray 0 = 90°, isalso a point of the curve, inasmuch as sin (180° - ^) = sin 0, POLAR COORDINATES 199 We… … Fia. 9 To make sure that the curve has not sharp corners at O andB, we must compute r for small values of 0 and also for valuesof 0 near 90°. d 1° 3° 5 85^ 88° r .53 .92 1.18 3.99 4.00- 90 The corresponding points, when plotted (Fig. 9), show thatthe curve is smooth at 0 and B. If we admit negative…
