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∫e2x−e−2xe2x+e−2xdx\int \frac{e^{2x} - e^{-2x}}{e^{2x} + e^{-2x}}dx is equal to

Solution

✅ Correct Option: 3

Given: ∫e2x−e−2xe2x+e−2xdx\int \frac{e^{2x} - e^{-2x}}{e^{2x} + e^{-2x}}dx

The numerator is almost the derivative of the denominator.

Let u=e2x+e−2xu = e^{2x} + e^{-2x}


Differentiate uu with respect to xx:

dudx=ddx(e2x)+ddx(e−2x)\frac{du}{dx} = \frac{d}{dx}(e^{2x}) + \frac{d}{dx}(e^{-2x})

dudx=2e2x−2e−2x\frac{du}{dx} = 2e^{2x} - 2e^{-2x}

dudx=2(e2x−e−2x)\frac{du}{dx} = 2(e^{2x} - e^{-2x})

Therefore: du=2(e2x−e−2x)dxdu = 2(e^{2x} - e^{-2x})dx

(e2x−e−2x)dx=12du(e^{2x} - e^{-2x})dx = \frac{1}{2}du


∫e2x−e−2xe2x+e−2xdx=∫1u⋅12du\int \frac{e^{2x} - e^{-2x}}{e^{2x} + e^{-2x}}dx = \int \frac{1}{u} \cdot \frac{1}{2}du

=12∫1udu= \frac{1}{2}\int \frac{1}{u}du

=12log⁡e∣u∣+C= \frac{1}{2}\log_e|u| + C


Replace uu with e2x+e−2xe^{2x} + e^{-2x}:

=12log⁡e∣e2x+e−2x∣+C= \frac{1}{2}\log_e|e^{2x} + e^{-2x}| + C

Therefore, ∫e2x−e−2xe2x+e−2xdx=12log⁡e∣e2x+e−2x∣+C\int \frac{e^{2x} - e^{-2x}}{e^{2x} + e^{-2x}}dx = \frac{1}{2}\log_e|e^{2x} + e^{-2x}| + C

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