Программа 51. Задача 69

>	restart;#Подбор сечения сжатого стержня

>	koeff[1]:=[1,0.99,0.96,0.94,0.92,0.89,0.86,0.81,0.75,0.69,0.60,0.52,0.45,0.40,0.36,0.32,0.29,0.26,0.23,0.21,0.19]:#сталь

>	koeff[2]:=[1,0.97,0.91,0.81,0.69,0.57,0.44,0.34,0.26,0.20,0.16]:#чугун

>	koeff[3]:=[1,0.99,0.97,0.93,0.87,0.8,0.71,0.61,0.48,0.38,0.31,0.26,0.22,0.18,0.16,0.14,0.12,0.11,0.1,0.09,0.08]:#дерево

>	phi:=proc(x,k) spline([i*10$i=0..nops(koeff[k])-1],koeff[k],x,linear);end:#cubic

>	P:=100:    # Нагрузка кН

>	sigma:=130:# Допускаемое напряжение МПа

>	mu:=1:     # Коэффициент приведения (1,0.5,0.7,2)

>	l:=1.1:    # Длина (м)

>	n:=2:      # чугун

>	K:=2*sqrt(3.):

>	b:=l*mu/lambda*K:

>	eq:=P-sigma*1E3*b^2*phi(lambda,n):

>	lambda:=fsolve(eq,lambda=0..200);

>

b;