Resolver desigualdad.
0 "algo" distinto de cero.
Es para acotar el resto de raíz de 2 en un pol. de Taylor de la función (1+x)^(1/2) Centrado en 0, de orden 3.
Entonces, si queda: [1/t^(7/2)] > 0 no me sirve, porque me diría que el error es cero y eso no es cierto.
Pregunta original: " Sea f(x)=(1+x)^(1/2). Usando el pol. de Taylor de orden 3 de f en a=0, calcular el valor aprox. de raiz de 2 que da dicho polinomio. Estimar el error. "
CarlosMath:
el límite cuando x--> 0 de (1+x)^(1/2) es 1, no veo ninguna raíz cuadrada de 2, será mejor que coloques la pregunta original, y de allí verás si la respuesta de conviene o no
Respuestas
Respuesta dada por:
2
derivemos
![f(x)=(1+x)^{1/2}\\ \\
f'(x)=\dfrac{1}{2}(1+x)^{-1/2}\to f'(0)=\dfrac{1}{2}\\ \\
f''(x)=-\dfrac{1}{4}(1+x)^{-3/2}\to f''(0)=-\dfrac{1}{4}\\\\
f'''(x)=\dfrac{3}{8}(1+x)^{-5/2}\to f'''(0)=\dfrac{3}{8}\\\\\\
f^{iv}(x)=-\dfrac{15}{16}(1+x)^{-7/2}\to f^{iv}(t)=-\dfrac{15}{16}(1+t)^{-7/2}\\\\\\
f(x)=1+\dfrac{1}{2\cdot 1! }x-\dfrac{1}{4\cdot 2!}x^2+\dfrac{3}{8\cdot 3!}x^3+E_3
f(x)=(1+x)^{1/2}\\ \\
f'(x)=\dfrac{1}{2}(1+x)^{-1/2}\to f'(0)=\dfrac{1}{2}\\ \\
f''(x)=-\dfrac{1}{4}(1+x)^{-3/2}\to f''(0)=-\dfrac{1}{4}\\\\
f'''(x)=\dfrac{3}{8}(1+x)^{-5/2}\to f'''(0)=\dfrac{3}{8}\\\\\\
f^{iv}(x)=-\dfrac{15}{16}(1+x)^{-7/2}\to f^{iv}(t)=-\dfrac{15}{16}(1+t)^{-7/2}\\\\\\
f(x)=1+\dfrac{1}{2\cdot 1! }x-\dfrac{1}{4\cdot 2!}x^2+\dfrac{3}{8\cdot 3!}x^3+E_3](https://tex.z-dn.net/?f=f%28x%29%3D%281%2Bx%29%5E%7B1%2F2%7D%5C%5C+%5C%5C%0Af%27%28x%29%3D%5Cdfrac%7B1%7D%7B2%7D%281%2Bx%29%5E%7B-1%2F2%7D%5Cto+f%27%280%29%3D%5Cdfrac%7B1%7D%7B2%7D%5C%5C+%5C%5C%0Af%27%27%28x%29%3D-%5Cdfrac%7B1%7D%7B4%7D%281%2Bx%29%5E%7B-3%2F2%7D%5Cto+f%27%27%280%29%3D-%5Cdfrac%7B1%7D%7B4%7D%5C%5C%5C%5C%0Af%27%27%27%28x%29%3D%5Cdfrac%7B3%7D%7B8%7D%281%2Bx%29%5E%7B-5%2F2%7D%5Cto+f%27%27%27%280%29%3D%5Cdfrac%7B3%7D%7B8%7D%5C%5C%5C%5C%5C%5C%0Af%5E%7Biv%7D%28x%29%3D-%5Cdfrac%7B15%7D%7B16%7D%281%2Bx%29%5E%7B-7%2F2%7D%5Cto+f%5E%7Biv%7D%28t%29%3D-%5Cdfrac%7B15%7D%7B16%7D%281%2Bt%29%5E%7B-7%2F2%7D%5C%5C%5C%5C%5C%5C%0Af%28x%29%3D1%2B%5Cdfrac%7B1%7D%7B2%5Ccdot+1%21+%7Dx-%5Cdfrac%7B1%7D%7B4%5Ccdot+2%21%7Dx%5E2%2B%5Cdfrac%7B3%7D%7B8%5Ccdot+3%21%7Dx%5E3%2BE_3%0A%0A)
![f(x)=1+\dfrac{1}{2}x-\dfrac{1}{8}x^2+\dfrac{3}{48}x^3+\left(-\dfrac{15}{16\cdot 4!}(1+t)^{-7/2}x^4\right)\\ \\ \\
f(x)=1+\dfrac{1}{2}x-\dfrac{1}{8}x^2+\dfrac{3}{48}x^3+\left(-\dfrac{15}{256}(1+t)^{-7/2}x^4\right)\\ \\
\sqrt{2}\approx f(1)=1+\dfrac{1}{2}-\dfrac{1}{8}+\dfrac{3}{48}\\ \\
\sqrt{2}\approx \dfrac{23}{16}\\ \\ \\
\boxed{\sqrt{2}\approx 1.4375}
f(x)=1+\dfrac{1}{2}x-\dfrac{1}{8}x^2+\dfrac{3}{48}x^3+\left(-\dfrac{15}{16\cdot 4!}(1+t)^{-7/2}x^4\right)\\ \\ \\
f(x)=1+\dfrac{1}{2}x-\dfrac{1}{8}x^2+\dfrac{3}{48}x^3+\left(-\dfrac{15}{256}(1+t)^{-7/2}x^4\right)\\ \\
\sqrt{2}\approx f(1)=1+\dfrac{1}{2}-\dfrac{1}{8}+\dfrac{3}{48}\\ \\
\sqrt{2}\approx \dfrac{23}{16}\\ \\ \\
\boxed{\sqrt{2}\approx 1.4375}](https://tex.z-dn.net/?f=f%28x%29%3D1%2B%5Cdfrac%7B1%7D%7B2%7Dx-%5Cdfrac%7B1%7D%7B8%7Dx%5E2%2B%5Cdfrac%7B3%7D%7B48%7Dx%5E3%2B%5Cleft%28-%5Cdfrac%7B15%7D%7B16%5Ccdot+4%21%7D%281%2Bt%29%5E%7B-7%2F2%7Dx%5E4%5Cright%29%5C%5C+%5C%5C+%5C%5C%0Af%28x%29%3D1%2B%5Cdfrac%7B1%7D%7B2%7Dx-%5Cdfrac%7B1%7D%7B8%7Dx%5E2%2B%5Cdfrac%7B3%7D%7B48%7Dx%5E3%2B%5Cleft%28-%5Cdfrac%7B15%7D%7B256%7D%281%2Bt%29%5E%7B-7%2F2%7Dx%5E4%5Cright%29%5C%5C+%5C%5C%0A%5Csqrt%7B2%7D%5Capprox+f%281%29%3D1%2B%5Cdfrac%7B1%7D%7B2%7D-%5Cdfrac%7B1%7D%7B8%7D%2B%5Cdfrac%7B3%7D%7B48%7D%5C%5C+%5C%5C%0A%5Csqrt%7B2%7D%5Capprox+%5Cdfrac%7B23%7D%7B16%7D%5C%5C+%5C%5C+%5C%5C%0A%5Cboxed%7B%5Csqrt%7B2%7D%5Capprox+1.4375%7D%0A)
Cuyo error es
![E_3=-\dfrac{15}{256}(1+t)^{-7/2}\;,\; t\in (0,1)\\ \\
\dfrac{1}{2}\ \textless \ \dfrac{1}{t+1}\ \textless \ 1\to \sqrt{\dfrac{1}{2}}^7\ \textless \ \sqrt{\dfrac{1}{t+1}}^7\ \textless \ 1\\ \\ \\
\boxed{|E_3|\leq \dfrac{15}{256}}
E_3=-\dfrac{15}{256}(1+t)^{-7/2}\;,\; t\in (0,1)\\ \\
\dfrac{1}{2}\ \textless \ \dfrac{1}{t+1}\ \textless \ 1\to \sqrt{\dfrac{1}{2}}^7\ \textless \ \sqrt{\dfrac{1}{t+1}}^7\ \textless \ 1\\ \\ \\
\boxed{|E_3|\leq \dfrac{15}{256}}](https://tex.z-dn.net/?f=E_3%3D-%5Cdfrac%7B15%7D%7B256%7D%281%2Bt%29%5E%7B-7%2F2%7D%5C%3B%2C%5C%3B+t%5Cin+%280%2C1%29%5C%5C+%5C%5C+%0A%5Cdfrac%7B1%7D%7B2%7D%5C+%5Ctextless+%5C+%5Cdfrac%7B1%7D%7Bt%2B1%7D%5C+%5Ctextless+%5C+1%5Cto+%5Csqrt%7B%5Cdfrac%7B1%7D%7B2%7D%7D%5E7%5C+%5Ctextless+%5C+%5Csqrt%7B%5Cdfrac%7B1%7D%7Bt%2B1%7D%7D%5E7%5C+%5Ctextless+%5C+1%5C%5C+%5C%5C+%5C%5C%0A%5Cboxed%7B%7CE_3%7C%5Cleq+%5Cdfrac%7B15%7D%7B256%7D%7D%0A)
es decir
![\sqrt{2}=1.4375+E_3 \sqrt{2}=1.4375+E_3](https://tex.z-dn.net/?f=%5Csqrt%7B2%7D%3D1.4375%2BE_3)
Cuyo error es
es decir
Preguntas similares
hace 6 años
hace 6 años
hace 6 años
hace 9 años
hace 9 años
hace 9 años