[填空题]
Ali is swimming in a public pool with s9 d*u,vqxcs3 zomee 9gvf263e cy.x7 nlcos g0ht, of his friends. At time t seconds, he encounters some waves with height,0egl3g e76s9xf.vh y n2co ct $h_1$(t)=0.15sin(3t) from big Bobby jumping into the pool, and waves of height
$h_2$(t)=0.08sin(3t+1.25) from small Suzie jumping into the pool. Both
$h_1$(t) and $h_2$ (t) are measured in metres.
1.Write, in the form h(t)=Asin(ωt+φ), an expression for the total height of the waves Ali encounters at time t seconds.
2.Find the times in the first 5 seconds when Ali isn't affected by any waves.
3.Find the first time when the waves reaching Ali has maximum height.
Hence the first time when the wave reaching Ali has max height is at s
