To integrate the function \( e^{x} \cdot x^{2} \), we can use the technique of integration by parts. This method is useful when dealing with the product of two functions.
Integration by Parts Formula
The formula for integration by parts is:
∫ u dv = uv - ∫ v du
Here, we need to choose \( u \) and \( dv \) from our function \( e^{x} \cdot x^{2} \).
Choosing u and dv
- Let: \( u = x^{2} \) (which simplifies when differentiated)
- Then: \( du = 2x \, dx \)
- Let: \( dv = e^{x} \, dx \)
- Then: \( v = e^{x} \)
Applying the Formula
Now, we can apply the integration by parts formula:
∫ \( e^{x} \cdot x^{2} \, dx = x^{2} \cdot e^{x} - ∫ e^{x} \cdot 2x \, dx \)
Integrating the Remaining Integral
Next, we need to integrate \( ∫ e^{x} \cdot 2x \, dx \) using integration by parts again:
- Let: \( u = 2x \)
- Then: \( du = 2 \, dx \)
- Let: \( dv = e^{x} \, dx \)
- Then: \( v = e^{x} \)
Applying the formula again gives:
∫ \( e^{x} \cdot 2x \, dx = 2x \cdot e^{x} - ∫ 2e^{x} \, dx \)
Final Steps
The integral of \( 2e^{x} \) is simply \( 2e^{x} \). So we have:
∫ \( e^{x} \cdot 2x \, dx = 2x \cdot e^{x} - 2e^{x} \)
Putting It All Together
Now, substituting back into our original integration:
∫ \( e^{x} \cdot x^{2} \, dx = x^{2} \cdot e^{x} - (2x \cdot e^{x} - 2e^{x}) + C \)
Thus, the final result is:
∫ e^{x} \cdot x^{2} \, dx = e^{x}(x^{2} - 2x + 2) + C