Ан
Анастасия
f(x0+дx,y0+дy) = f(x0,y0) + d(f(x0,y0))
f(x0+дx,y0+дy) = f(x0,y0) + f'x(x0,y0)*дx + f'y(x0,y0)*дy
f(x,y) = sqrt5(x^2+y^2+15)
f'x(x,y) = (1/5)*(x^2+y^2+15)^(-4/5)*2x
f'y(x,y) = (1/5)*(x^2+y^2+15)^(-4/5)*2y
f(x0,y0)=sqrt5(4^2 + 1^2 +15) = sqrt5(32) = 2
f'x(x0,y0) = (1/5)*(x0^2+y0^2+15)^(-4/5)*2x0 = (1/5)*(32)*(-4/5)*2*4 = (1/5*16)*8 = 1/10
f'y(x0,y0) = (1/5)*(x0^2+y0^2+15)^(-4/5)*2y0 = (1/5*16)*2*1 = 1/40
f(x0+дx,y0+дy) = 2 + (1/10)*0,03 - (1/40)*0,04 = 2,002
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