[填空题]
A boat, whose speed in still water is 1.75 m/s, must aim upstream at anne2z0rka v4zppxz8o (0 t.sh-m7)xzs angle ohps4l,/z f y3gf p l3fg/h,z y4s$26.3^{\circ}$ (with respect to a line perpendicular to the shore) in order to travel directly across the stream. (a) Determine the speed of the current. $m/s$ (b) Determine the resultant speed of the boat with respect to the shore $m/s$
