how to solve integration of e^x( x.cosx+sinx ) dx ?
first uv rule on whole n then again inside for X. cosx... u will get it
how to solve integration of e^x( x.cosx+sinx ) dx ?
Introduction:
To solve the integration of e^x(x.cosx sinx) dx, we will use the technique of integration by parts. This method allows us to integrate a product of two functions by applying the product rule in reverse. The formula for integration by parts is as follows:
∫ u dv = uv - ∫ v du
Where u and v are functions of x, and du and dv are their respective differentials.
Step 1: Identify u and dv:
In our case, we can select u = x and dv = e^x(cosx sinx) dx.
Step 2: Calculate du and v:
To find du, we differentiate u with respect to x, resulting in du = dx.
To find v, we need to integrate dv. This requires simplifying the expression e^x(cosx sinx). We can use the trigonometric identities sin2x = 2sinxcosx and cos2x = cos^2x - sin^2x.
Let's rewrite dv:
dv = e^x(cosx sinx) dx
= e^x(sin2x/2) dx
= (e^x/2)(sin2x) dx
= (e^x/2)(2sinxcosx) dx
= e^x sinx cosx dx
Integrating dv, we obtain:
v = ∫ e^x sinx cosx dx
Step 3: Apply integration by parts:
Using the formula for integration by parts, we have:
∫ u dv = uv - ∫ v du
Applying this to our problem, we get:
∫ x e^x sinx cosx dx = x ∫ e^x sinx cosx dx - ∫ (∫ e^x sinx cosx dx) dx
Simplifying, we have:
I = x ∫ e^x sinx cosx dx - ∫ I dx
I = x ∫ e^x sinx cosx dx - ∫ x ∫ e^x sinx cosx dx dx
Step 4: Solve for the unknown integral:
To solve the integral ∫ e^x sinx cosx dx, we can use integration by parts again.
Let's identify u and dv:
u = sinx, dv = e^x cosx dx
Calculating du and v:
du = cosx dx
v = ∫ e^x cosx dx
We can integrate v using integration by parts:
∫ e^x cosx dx = e^x sinx - ∫ e^x sinx dx
Simplifying, we have:
∫ e^x cosx dx = e^x sinx - ∫ e^x sinx dx
Substituting this back into our main equation, we get:
I = x(e^x sinx - ∫ e^x sinx dx) - ∫ x(e^x sinx cosx dx) dx
Step 5: Simplify and finalize the integral:
We now have an equation with two unknown integrals. To solve for I, we need to simplify and rearrange the terms.
Expanding the equation, we have:
I = x(e^x sinx) -
To make sure you are not studying endlessly, EduRev has designed JEE study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in JEE.