Using integration by parts: $\int u\,dv = uv - \int v\,du$.
Let $u = \cos^{-1}(2x)$ and $dv = dx$.
Then $du = -\frac{2}{\sqrt{1-(2x)^2}}dx = -\frac{2}{\sqrt{1-4x^2}}dx$, and $v = x$.
Thus:
$\int \cos^{-1}(2x)\,dx = x\cos^{-1}(2x) - \int x\left(-\frac{2}{\sqrt{1-4x^2}}\right)dx = x\cos^{-1}(2x) + \int \frac{2x}{\sqrt{1-4x^2}}dx$.
To evaluate the remaining integral, let $w = 1 - 4x^2$, so $dw = -8x\,dx \implies 2x\,dx = -\frac{1}{4}dw$.
Then $\int \frac{2x}{\sqrt{1-4x^2}}dx = -\frac{1}{4}\int w^{-1/2}dw = -\frac{1}{4}(2w^{1/2}) = -\frac{1}{2}\sqrt{1-4x^2}$.
Combining terms gives:
$\int \cos^{-1}(2x)\,dx = x\cos^{-1}(2x) - \frac{1}{2}\sqrt{1-4x^2} + C$.
Detailed analysis of options:
- $x\cos^{-1}(2x) - \frac{1}{2}\sqrt{1-4x^2} + C$ is the correct result.
- Uses $\sin^{-1}$ instead of $\cos^{-1}$.
- Has a plus sign instead of minus sign.
- Uses $\sin^{-1}$ and plus sign.
खंडशः समाकलन (integration by parts) का प्रयोग करने पर: $\int u\,dv = uv - \int v\,du$.
माना $u = \cos^{-1}(2x)$ तथा $dv = dx$.
तब $du = -\frac{2}{\sqrt{1-4x^2}}dx$ और $v = x$.
अतः:
$\int \cos^{-1}(2x)\,dx = x\cos^{-1}(2x) - \int x\left(-\frac{2}{\sqrt{1-4x^2}}\right)dx = x\cos^{-1}(2x) + \int \frac{2x}{\sqrt{1-4x^2}}dx$.
शेष समाकल हेतु, माना $w = 1 - 4x^2 \implies dw = -8x\,dx \implies 2x\,dx = -\frac{1}{4}dw$.
अतः $\int \frac{2x}{\sqrt{1-4x^2}}dx = -\frac{1}{4}(2\sqrt{w}) = -\frac{1}{2}\sqrt{1-4x^2}$.
अंतिम मान:
$x\cos^{-1}(2x) - \frac{1}{2}\sqrt{1-4x^2} + C$.
विकल्पों का विस्तृत विश्लेषण:
- $x\cos^{-1}(2x) - \frac{1}{2}\sqrt{1-4x^2} + C$ सही उत्तर है।
- $\cos^{-1}$ के स्थान पर $\sin^{-1}$ लिखा है।
- ऋण चिन्ह के स्थान पर धन चिन्ह लिखा है।
- गलत है।