Nystrom, John W. (John William), 1824-1885 · Philadelphia, J.B. Lippincott · leaf 103
• 9- To find the length of a Spiral. 7 Ttr* I = nrn = —, n = nr P P=«L*=L. p- Pitch.I n … 80. To find the length of a Spiral.l = rt7i(R+r), *-5 (*■—). 81. Periphery of an Ellipse.
Mechanical engineering · Engineering
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