Tolong kasih tau, trims

[tex]\displaystyle f(x)=20x^{\frac72}+2x^{\frac52}+10x\\\\f'(x)=20\cdot\frac72x^{\frac72-1}+2\cdot\frac52x^{\frac52-1}+10\\f'(x)=70x^{\frac52}+5x^{\frac32}+10\\\\f''(x)=70\cdot\frac52x^{\frac52-1}+5\cdot\frac32x^{\frac32-1}\\f''(x)=175x^{\frac32}+\frac{15}2x^{\frac12}\\f''(4)=175(4)^{\frac32}+\frac{15}2(4)^{\frac12}\\f''(4)=175(8)+\frac{15}2(2)\\f''(4)=1400+15\\\boxed{\boxed{f''(4)=1415}}[/tex]

[tex]f(x) = 20 x^{3 \frac{1}{2} } + 2 x^{2 \frac{1}{2} } + 10x \\ f'(x) = 3 \frac{1}{2}.20x^{ \frac{5}{2} } + 2 \frac{1}{2} . 2x^{ \frac{3}{2} } + 1.10 \\ f'(x) = 70 x^{ \frac{5}{2} }+5 x^{ \frac{3}{2} } + 10 \\ f''(x) = \frac{5}{2}. 70 x^{ \frac{3}{2} } + \frac{3}{2}.5 x^{ \frac{1}{2} } \\ f''(x) = 175 x^{ \frac{3}{2} }+ \frac{15}{2} x^{ \frac{1}{2} } \\ f''(4) = 175(4)^{ \frac{3}{2} } + \frac{15}{2} (4)^{ \frac{1}{2} } \\ f''(4) = 1400 + 15 \\ f''(4) =1415[/tex]