Higher Engineering Mathematics, Sixth Edition

Irregular areas, volumes and mean values of waveforms 211

5. An indicator diagram of a steam engine is
   12cm long. Seven evenly spaced ordinates,
   including the end ordinates, are measured as
   follows:

5.90,5.52,4.22,3.63,3.32,3.24,3.16cm

Determine the area of the diagram and the

mean pressure in the cylinder if 1cm repre-

sents 90kPa. [49.13cm^2 , 368.5kPa]