Find \(\int_{1}^{2}(x+2) \sin x \mathrm{~d} x\).

Short Answer

Expert verified
Question: Evaluate the integral of \((x+2) \sin x\) with respect to \(x\) within the limits of \(1\) and \(2\). Answer: The evaluated integral is \(-4\cos(2) + \sin(2) + 3\cos(1) - \sin(1)\).

Step by step solution

01

Identify the integration by parts formula

Recall the integration by parts formula: \(\int u dv = uv-\int v du\), where \(u\) and \(dv\) are the chosen parts of the function being integrated.
02

Choose \(u\) and \(dv\)

From the function \((x+2) \sin x\), we choose: \(u = x+2\) \(dv = \sin x dx\)
03

Differentiate \(u\) and integrate \(dv\)

We differentiate \(u\) with respect to \(x\) to get its differential \(du\): \(\frac{d}{dx}(x+2) = 1\), so \(du=dx\) Next, we integrate \(dv = \sin x dx\) with respect to \(x\): \(\int \sin x dx = -\cos x + C\), so \(v=-\cos x\)
04

Apply the integration by parts formula

Now we can apply the integration by parts formula from step 1, with our values for \(u\), \(v\), and \(du\): \(\int (x+2) \sin x dx = (x+2)(-\cos x) - \int(-\cos x) dx\)
05

Calculate the remaining integral and combine terms

Integrate \(\cos x\) with respect to \(x\): \(\int (-\cos x) dx = -\sin x + C\) Substitute this result into the expression above: \(\int (x+2) \sin x dx = -(x+2)\cos x + \sin x + C\)
06

Evaluate the integral within the given limits

Now apply the given limits of integration, \(1\) and \(2\), to the integral: \(\big[-(x+2)\cos x + \sin x\big]_1^2\) = \(\big[ -(2+2)\cos(2) + \sin(2) \big] - \big[ -(1+2)\cos(1) + \sin(1) \big]\) \(=-4\cos(2) + \sin(2) + 3\cos(1) - \sin(1)\) This is the final evaluated integral within the given limits for \(\int_{1}^{2}(x+2) \sin x \mathrm{~d} x\).

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Study anywhere. Anytime. Across all devices.

Sign-up for free