Set up integral: Set up the integral for evaluation.We need to evaluate the integral of the function x4+16xdx from 0 to 3.
Find substitution: Look for a substitution that simplifies the integral.Notice that the denominator contains an expression of the form x4+16, which suggests a trigonometric substitution. However, since the x4 term complicates a direct trigonometric substitution, we might consider a substitution that simplifies the x4 term. Let's try the substitution u=x2, which implies that du=2xdx.
Rewrite in terms of u: Rewrite the integral in terms of u.Substituting u=x2 and du=2xdx into the integral, we get:∫03x4+16xdx=21∫03u2+16duWe divided by 2 because we replaced 2xdx with du.
Evaluate with new variable: Evaluate the integral with the new variable u. Now we have the integral 21∫03u2+16du, which is a standard form that can be solved using a trigonometric substitution or by recognizing it as a form of the inverse hyperbolic sine function, asinh(4u). The derivative of asinh(4u) is u2+161, which matches our integrand.
Find antiderivative: Find the antiderivative.The antiderivative of u2+161 is asinh(4u), so the antiderivative of our integral is:21asinh(4u)+C
Substitute and evaluate: Substitute back in terms of x and evaluate the definite integral.Substituting back u=x2, we have:21 asinh(4x2) + CNow we can evaluate the definite integral from 0 to 3:21 [asinh(4(3)2) - asinh(402)]= 21 [asinhu=x21 - asinh0]
Calculate inverse hyperbolic sine: Calculate the values of the inverse hyperbolic sine function.asinh(43) can be found using a calculator or a table of values, and asinh(0) is 0.So the definite integral is:21[asinh(43)−0]= 21asinh(43)
Provide final answer: Provide the final answer.The evaluated integral from 0 to 3 of (xdx)/(x4+16) is 21asinh(43).
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