quick question. (1 Viewer)

[spikestar]

can some1 plz give me a hand with this question thanks.

 

[Riviet]

y=g.sec(pi.x/24) + h

When y=0, x=+8

Substitute into equation, rearrange to get h=-2g (1)

When x=0, y=-8

Substitute into equation, rearrange to get g+h=-8 (2)

Solve (1) and (2) simultaneously to get g=8 and h=-16

.'. y=8sec(pi.x/24) - 16

When water surface is 11m, ie when x=5.5,

y= 8/cos(5.5pi/24) - 16

depth = 8-y
= 8-[8/cos(5.5pi/24) - 16]
=13.36m (2dp)

When depth of water is 4m, ie when y=-4,
-4=8/cos(pi.x/24) - 16
Solving this yields x=6.42529.....
.'. surface of water = 2x
=12.85m (2dp)