[填空题]
The tip of a large wind turbine's blade rotates at a constant spe tnk 7v(dtz;m8f,w+v *p ok4s ax+naq2s8acv*ed on a ,drz;o;6u izxsg r;c pfho;+/windy da/,hzr z+drsc go;x; 6 fuop;i;y. Its height, $H$ , in metres, above the ground is modelled by the function
H(t)=52sin(60$^{\circ}$$\times$t)+80,where $t$ is the elapsed time, in seconds, since the turbine was accelerated to its max speed.
1.Write down the minimum height of the blade's tip above the ground. $H_{min}$ = m
2.Find the height of the blade's tip above the ground after 88 seconds. H = m
3.Find the time it takes for the blade's tip to complete one full revolution.
