1.

Show that the function `f(x)=2x-|x|`is continuous but notdifferentiable at `x=0`

Answer» `f(x)=2x-x,x>=0`
`f(x)=2x-(-x),x<0`
f(x) is continuous when lim f(x)=limf(x)=f(0)
`LHL=lim_(x->0^-)(3x)=0`
`RHL=lim_(x->0^+)=0`
`f(0)=0`
f(x) is differential only when LHD=RHD
`LHD=lim_(x->o^-)(f(x)-f(0))/(x-0)=lim_(x->0^-)((3x-0)/(x-0))=3`
`RHD=lim_(x->0^+)((f(x)-f(0))/(x-0))=lim_(x->0^+)((x-0)/(x-0))=1`
`LHD!=RHD`
f(x) is not differential at x=0.


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