4. berdasarkan formula $T'(x)=\lim_{t\to x}\frac{f(t)-f(x)}{t-x}$, tentukan formula dari $T'(x)$ untuk fungsi berikut.
a. $T(x)=3x-2$
b. $T(x)=\sqrt{2+3x}$
c. $T(x)=\frac{1}{x\sqrt{x}}$
d. $T(x)=\frac{1}{x^2\sqrt{x}}$
Jawab:
a. $T(x)=3x-2$
$T(t)=3t-2$
$T'(x)=\lim_{t\to x}\frac{f(t)-f(x)}{t-x}$
$T'(x)=\lim_{t\to x}\frac{(3t-2)-(3x-2)}{t-x}$
$T'(x)=\lim_{t\to x}\frac{(3t-3x}{t-x}$
$T'(x)=\lim_{t\to x}\frac{(3(t-x)}{t-x}$
$T'(x)=\lim_{t\to x}3$
$T'(x)=3$
b. $T(x)=\sqrt{2+3x}$
$T(t)=\sqrt{2+3t}$
$T'(x)=\lim_{t\to x}\frac{f(t)-f(x)}{t-x}$
$T'(x)=\lim_{t\to x}\frac{\sqrt{2+3t}-\sqrt{2+3x}}{t-x}$
$T'(x)=\lim_{t\to x}\left[\frac{\sqrt{2+3t}-\sqrt{2+3x}}{t-x}\right]\left[\frac{\sqrt{2+3t}+\sqrt{2+3x}}{\sqrt{2+3t}+\sqrt{2+3x}}\right]$
$T'(x)=\lim_{t\to x}\frac{(2+3t)-(2+3x)}{(t-x)(\sqrt{2+3t}+\sqrt{2+3x})}$
$T'(x)=\lim_{t\to x}\frac{3t-3x}{(t-x)(\sqrt{2+3t}+\sqrt{2+3x})}$
$T'(x)=\lim_{t\to x}\frac{3(t-x)}{(t-x)(\sqrt{2+3t}+\sqrt{2+3x})}$
$T'(x)=\lim_{t\to x}\frac{3}{\sqrt{2+3t}+\sqrt{2+3x}}$
$T'(x)=\frac{3}{\sqrt{2+3x}+\sqrt{2+3x}}$
$T'(x)=\frac{3}{2\sqrt{2+3x}}$
c. $T(x)=\frac{1}{x\sqrt{x}}$
$T(t)=\frac{1}{t\sqrt{t}}$
$T'(x)=\lim_{t\to x}\frac{f(t)-f(x)}{t-x}$
$T'(x)=\lim_{t\to x}\frac{\frac{1}{t\sqrt{t}}-\frac{1}{x\sqrt{x}}}{t-x}$
$T'(x)=\lim_{t\to x}\frac{x\sqrt{x}-t\sqrt{t}}{(t-x)(t\sqrt{t})(x\sqrt{x})}$
$T'(x)=\lim_{t\to x}\left[\frac{x\sqrt{x}-t\sqrt{t}}{(t-x)(t\sqrt{t})(x\sqrt{x})}\right]\left[\frac{\sqrt{x}+\sqrt{t}}{\sqrt{x}+\sqrt{t}}\right]$
$T'(x)=\lim_{t\to x}\frac{x^2-t^2}{(t-x)(t\sqrt{t})(x\sqrt{x})(\sqrt{x}+\sqrt{t})}$
$T'(x)=\lim_{t\to x}\frac{-(t^2-x^2)}{(t-x)(t\sqrt{t})(x\sqrt{x})(\sqrt{x}+\sqrt{t})}$
$T'(x)=\lim_{t\to x}\frac{-(t-x)(t+x)}{(t-x)(t\sqrt{t})(x\sqrt{x})(\sqrt{x}+\sqrt{t})}$
Comments
Post a Comment