Answer:
[tex]\frac{dw}{dr} = \frac{8\cdot r}{4\cdot r^{2}-t^{2}+5\cdot s^{2}}[/tex], [tex]\frac{dw}{ds} = \frac{10\cdot s}{4\cdot r^{2}-t^{2}+5\cdot s^{2}}[/tex], [tex]\frac{dw}{dt} = -\frac{2\cdot t}{4\cdot r^{2}-t^{2}+5\cdot s^{2}}[/tex]
Step-by-step explanation:
We proceed to derive each expression by rule of chain. Let be [tex]w = \ln (x+2\cdot y + 3\cdot z)[/tex], [tex]x = r^{2}+t^{2}[/tex], [tex]y = s^{2}-t^{2}[/tex] and [tex]z = r^{2}+s^{2}[/tex]:
[tex]\frac{dw}{dr} = \frac{\frac{dx}{dr}+2\cdot \frac{dy}{dr} +3\cdot \frac{dz}{dr} }{x+2\cdot y + 3\cdot z}[/tex]
[tex]\frac{dx}{dr} = 2\cdot r[/tex]
[tex]\frac{dy}{dr} = 0[/tex]
[tex]\frac{dz}{dr} = 2\cdot r[/tex]
[tex]\frac{dw}{dr} = \frac{8\cdot r}{(r^{2}+t^{2})+2\cdot (s^{2}-t^{2})+3\cdot (r^{2}+s^{2})}[/tex]
[tex]\frac{dw}{dr} = \frac{8\cdot r}{4\cdot r^{2}-t^{2}+5\cdot s^{2}}[/tex] (1)
[tex]\frac{dw}{ds} = \frac{\frac{dx}{ds}+2\cdot \frac{dy}{ds} +3\cdot \frac{dz}{ds} }{x+2\cdot y + 3\cdot z}[/tex]
[tex]\frac{dx}{ds} = 0[/tex]
[tex]\frac{dy}{ds} = 2\cdot s[/tex]
[tex]\frac{dz}{ds} = 2\cdot s[/tex]
[tex]\frac{dw}{ds} = \frac{10\cdot s}{(r^{2}+t^{2})+2\cdot (s^{2}-t^{2})+3\cdot (r^{2}+s^{2})}[/tex]
[tex]\frac{dw}{ds} = \frac{10\cdot s}{4\cdot r^{2}-t^{2}+5\cdot s^{2}}[/tex] (2)
[tex]\frac{dw}{dt} = \frac{\frac{dx}{dt}+2\cdot \frac{dy}{dt} +3\cdot \frac{dz}{dt} }{x+2\cdot y + 3\cdot z}[/tex]
[tex]\frac{dx}{dt} = 2\cdot t[/tex]
[tex]\frac{dy}{dt} = -2\cdot t[/tex]
[tex]\frac{dz}{dt} = 0[/tex]
[tex]\frac{dw}{dt} = -\frac{2\cdot t}{(r^{2}+t^{2})+2\cdot (s^{2}-t^{2})+3\cdot (r^{2}+s^{2})}[/tex]
[tex]\frac{dw}{dt} = -\frac{2\cdot t}{4\cdot r^{2}-t^{2}+5\cdot s^{2}}[/tex] (3)
