[填空题]
Ali is swimming in a puv4w6 ip(mde 6s n2p6ya.a:pgsay9p t- .j v0ekblic pool with some of his friends. At time t seconds, he encounters some wavespsk .-e:0ajv9 .ygpat with height
$h_1$(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
