Find the indefinite integral. (Remember the constant of integration.) \[ \int \frac{e^{2 x}}{49+e^{4 x}} d x \]
Real Tutor Solution
Answer
Solution
Reviewed and approved by the UpStudy tutoring team
Mind Expander
To solve the integral \[ \int \frac{e^{2x}}{49+e^{4x}} \, dx, \] we can start by using a substitution. Let \[ u = e^{2x} \quad \Rightarrow \quad du = 2e^{2x} \, dx \quad \Rightarrow \quad dx = \frac{du}{2u}. \] Then, we rewrite the integral in terms of \( u \): \[ \int \frac{u}{49 + u^2} \cdot \frac{du}{2u} = \int \frac{1}{2(49 + u^2)} \, du. \] Now, the integral simplifies to \[ \frac{1}{2} \int \frac{1}{49 + u^2} \, du. \] The integral \[ \int \frac{1}{a^2 + u^2} \, du = \frac{1}{a} \tan^{-1} \left( \frac{u}{a} \right) + C, \] where \( a = 7 \) (since \( 49 = 7^2 \)). Thus, we get: \[ \frac{1}{2} \cdot \frac{1}{7} \tan^{-1} \left( \frac{u}{7} \right) + C = \frac{1}{14} \tan^{-1} \left( \frac{e^{2x}}{7} \right) + C. \] Therefore, the final answer to the integral is: \[ \int \frac{e^{2x}}{49 + e^{4x}} \, dx = \frac{1}{14} \tan^{-1} \left( \frac{e^{2x}}{7} \right) + C. \]