Show that the following functions are not differentiable at the indicated value of x.

Find the derivative of the function g(t) = \(({t-2\over 2t+1})^9\) .

Differentiate the following: \(y=\left(x^2+1\right) \sqrt[3]{x^2+2}\)

Differentiate: y = sin (tan(\(\sqrt{sin x}\)))

Find \({dy\over dx}\) if sin y = ycos 2x

Differentiate: \(y={x^{3\over4}\sqrt{x^2+1}\over (3x+2)^5}\)

Find \({d^2y\over dx^2}\) if x² + y² = 4.

Find the derivatives of the following : y = x^cosx

Find the derivatives of the following : x^y = y^x

Find the derivative of the tan (x + y) + tan (x - y) = x