Ball, W. W. Rouse (Walter William Rouse), 1850-1925 · London : Macmillan · leaf 119
in the same way as before we have ^; sin a = u sin {B + a), or i; sin a = t^ sin (f>, where (f) = angle WAS — tt- 0 -a. Hence i; = w sin <^ cosec a. … Let w be the component velocity of the boat in the teeth of the wind, that is, in the direction AW. Then we have w = V cos BA IT = 2; cos (a + <^) = 1^ sin <^ cosec jl cos (a + </>). If a is constant, this is a maximum when <^ = Jtt — Ja; and, if <^ has this value, then ^(; = -^ 2^ (cosec a — 1).…
