Question #ab1ff

2 Answers
Dec 19, 2017

# dy/dx={(sinx)^sqrtx(2xcotx+lnsinx)}/(2sqrtx).#

Explanation:

Given that, #y=(sinx)^sqrtx.#

Taking Natural Log. of both sides, and, using #lna^m=mlna,#

#lny=ln{(sinx)^sqrtx}=sqrtx*lnsinx.#

Using the Product Rule to diff. both sides w.r.t. #x,# we get,

#d/dx{lny}=d/dx{sqrtx*lnsinx}, i.e., #

# d/dx{lny}=sqrtxd/dx{lnsinx}+(lnsinx)d/dxsqrtx....(star).#

Here, by the Chain Rule,

#d/dx{lny}=d/dy{lny}*dy/dx=1/y*dy/dx.#

Similarly, #d/dx{lnsinx}=1/sinx*d/dx{sinx}=cosx/sinx=cotx#.

Utilising these in #(star),# we get,

#1/ydy/dx=sqrtx*cotx+(lnsinx)(1/2*x^(1/2-1)),#

#=sqrtx*cotx+(lnsinx)/(2sqrtx), or,#

#=(2xcotx+lnsinx)/(2sqrtx).#

# rArr dy/dx={y(2xcotx+lnsinx)}/(2sqrtx).#

Since, #y=(sinx)^sqrtx,#

# dy/dx={(sinx)^sqrtx(2xcotx+lnsinx)}/(2sqrtx).#

Enjoy Maths.!

Dec 19, 2017

Let's see.

Explanation:

Given #rarr#

#y=(sinx)^(sqrtx)#.......(1).

Taking "log" on both sides,

#color(red)(logy=sqrtxlog(sinx))#

Now differentiating w.r.t #x# by chain rule #rarr#

#:.1/ycdot(dy/dx)=1/(2sqrtx)cdotlog(sinx)+sqrtxcdot(cosx/sinx)#

#:.1/ycdot(dy/dx)=log(sinx)/(2sqrtx) +sqrtxcotx#

#:.dy/dx=(ylogsinx)/(2sqrtx) +ysqrtxcotx#

Now from equation (1) #rarr#

#:.color(red)(dy/dx=((sinx)^(sqrtx)cdotlog(sinx))/(2sqrtx)+((sinx)^(sqrtx)sqrtxcotx))#

#:.color(red)(dy/dx=(sinx)^(sqrtx)(log(sinx)/(2sqrtx)+sqrtxcotx))#

Hope it Helps:)