Mathematics - 5 September 2007

hi all

The height (h) in metres above ground of a tip of minute hand can be modelled with this equation

h = 90 + 3.5 sin ( pi * t / 30 + pi / 2 )

calculate height above ground when the tip of minute hand is at 20 minutes past midnight.

i get the answer 88.25 m but i think it is wrong.

my working is:

90 + 3.5 sin ( pi * 20 / 30 + pi / 2) i took the height as 20, as the minute hand was at 20 past midnite. hence only 20 mins if we take the 24 hr clock 00.20 so used 20 as the height.

any help appreciated.

Thanks
l1khs

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