Given:
[tex]f(x)=\frac{4}{5}x^5[/tex]Required:
[tex]f\placeholder{⬚}^{^{\prime}}(x)[/tex][tex]\begin{gathered} if\text{ }f(x)=ax^n \\ then, \\ f\placeholder{⬚}^{^{\prime}}(x)=anx^{n-1} \\ so^{\prime}, \\ f\placeholder{⬚}^{^{\prime}}(x)=\frac{4}{5}\times5\times x^{5-1}=4x^4 \end{gathered}[/tex][tex]f\placeholder{⬚}^{^{\prime}}(x)=4x^4[/tex]