Answer:
[tex]\infty[/tex]
Step-by-step explanation:
We are given that
[tex]d(t)=\frac{100}{5+4sint}[/tex]
[tex]t=\infty[/tex]
[tex]\lim_{t\rightarrow \infty}d(t)=\lim_{t\rightarrow}\frac{100}{5+4sint}[/tex]
[tex]suppose a=\frac{1}{t}=\frac{1}{\infty}=0[/tex]
[tex]\lim_{a\rightarrow 0}\frac{100}{5+4sin\frac{1}{a}}[/tex]
[tex]\lim_{a\rightarrow 0}\frac{100}{5+\frac{4}{a}\times \frac{sin\frac{1}{a}}{\frac{1}{a}}}[/tex]
We know that [tex]\lim_{x\rightarrow 0}\frac{sinx}{x}=1[/tex]
[tex]\frac{100}{5+\infty}=0[/tex]
[tex]lim_{t\rightarrow\infty}d(t)=\lim_{a\rightarrow 0}\frac{1}{d(a)}[/tex]
[tex]\lim_{t\rightarrow \infty}d(t)=\frac{1}{0}=\infty[/tex]