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If y=[21+xb−a+xc−a+21+xc−b+xa−b+21+xa−c+xb−c]xy = \left[\dfrac{2}{1+x^{b-a}+x^{c-a}} + \dfrac{2}{1+x^{c-b}+x^{a-b}} + \dfrac{2}{1+x^{a-c}+x^{b-c}}\right]^x, then dydx\dfrac{dy}{dx} is equal to :

Solution

✅ Correct Option: 2

Put u=xau = x^a, v=xbv = x^b, w=xcw = x^c. The three terms become 2uu+v+w\frac{2u}{u+v+w}, 2vu+v+w\frac{2v}{u+v+w} and 2wu+v+w\frac{2w}{u+v+w}, which sum to 22. So y=2xy = 2^x and dydx=2xlog⁡e2\frac{dy}{dx} = 2^x\log_e 2.

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