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Question

Mathematics Question on Continuity and differentiability

Differentiate the function with respect to xx.
xx2sinxx^x-2^{sinx}

Answer

The correct answer is dydx=xx(1+logx)2sinxcosxlog2∴\frac{dy}{dx}=x^x(1+log\,x)-2^{sinx}cos\,xlog\,2
Let y=xx2sinxy=x^x-2^{sinx}
Also,let xx=ux^x=u and 2sinx=v2^{sinx}=v
y=uv∴y=u-v
dydx=dudxdvdx⇒\frac{dy}{dx}=\frac{du}{dx}-\frac{dv}{dx}
u=xxu=x^x
Taking logarithm on both the sides,we obtain
logu=xlogxlog\,u=xlog\,x
Differentiating both sides with respect to xx,we obtain
1ududx=[ddx(x)×logx+x×ddx(logx)]\frac{1}{u}\frac{du}{dx}=[\frac{d}{dx}(x)\times log\,x+x\times \frac{d}{dx}(logx)]
dudx=u[1×logx+x×1x]⇒\frac{du}{dx}=u[1\times log\,x+x\times \frac{1}{x}]
dudx=xx(logx+1)⇒\frac{du}{dx}=x^x(logx+1)
dudx=xx(1+logx)⇒\frac{du}{dx}=x^x(1+log\,x)
v=2sinxv=2^{sinx}
Taking logarithm on both the sides with respect to xx,we obtain
logv=sinx.log2log\,v=sin\,x.log\,2
Differentiating both sides with respect to xx,we obtain
1vdvdx=log2.ddx(sinx)\frac{1}{v}\frac{dv}{dx}=log2.\frac{d}{dx}(sin\,x)
dvdx=vlog2cosx⇒\frac{dv}{dx}=v\,log\,2\,cosx
dvdx=2sinxcosxlog2⇒\frac{dv}{dx}=2^{sinx}cos\,xlog\,2
dydx=xx(1+logx)2sinxcosxlog2∴\frac{dy}{dx}=x^x(1+log\,x)-2^{sinx}cos\,xlog\,2