Harison ,
[tex3]\text{y}(\text{t})=(\ln\sqrt{\text{a}.\text{b}^3}).\text{t}[/tex3]
[tex3]\text{y}(\text{t})=[\ln(\text{a}^{\frac{1}{2}}.\text{b}^{\frac{3}{2}})].\text{t}[/tex3]
[tex3]\text{y}(\text{t})=[\ln \text{a}^{\frac{1}{2}}+\ln \text{b}^{\frac{3}{2}}].\text{t}[/tex3]
[tex3]\text{y}(\text{t})=\left[\frac{1}{2}.\ln \text{a}+\frac{3}{2}.\ln \text{b}\right].\text{t}[/tex3]
Substituindo os valores dados:
[tex3]\text{y}(\text{t})=\left[\frac{1}{2}.2+\frac{3}{2}.4\right].\text{t}[/tex3]
[tex3]\text{y}(\text{t})=7.\text{t}[/tex3]
Para [tex3]\text{t}=2[/tex3]
[tex3]\text{y}(\text{t})=7.2[/tex3]
[tex3]{\color{red}\boxed{\text{y}(\text{t})=14}}[/tex3]