Differentiate xsin⁡x,x>0x^{\sin x}, x>0 w.r.t. xx.

Answer: dydx=xsin⁡x(sin⁡xx+cos⁡xlog⁡x)\frac{dy}{dx} = x^{\sin x} \left(\frac{\sin x}{x} + \cos x \log x\right)

Step-by-step solution

Step 1: Introduce a variable and take logarithm

To differentiate a function of the form f(x)g(x)f(x)^{g(x)}, it is often helpful to use logarithmic differentiation. We first set the given expression equal to yy, and then take the natural logarithm of both sides. This allows us to use the logarithm property log⁡(ab)=blog⁡a\log(a^b) = b \log a to bring the exponent down.

Step 2: Differentiate both sides with respect to x

Now, we differentiate both sides of the equation with respect to xx. On the left side, we use the chain rule for log⁡y\log y. On the right side, we will need to apply the product rule.

Step 3: Apply the product rule

We apply the product rule, which states that ddx(uv)=udvdx+vdudx\frac{d}{dx}(uv) = u \frac{dv}{dx} + v \frac{du}{dx}. Here, u=sin⁡xu = \sin x and v=log⁡xv = \log x. We know that the derivative of log⁡x\log x is 1x\frac{1}{x} and the derivative of sin⁡x\sin x is cos⁡x\cos x. Substituting these into the product rule gives us the derivative of the right side.

Step 4: Solve for dy/dx

Now we have an expression for 1ydydx\frac{1}{y} \frac{dy}{dx}. To find dydx\frac{dy}{dx}, we multiply both sides of the equation by yy.

Step 5: Substitute y back into the equation

Finally, we substitute the original expression for yy, which was xsin⁡xx^{\sin x}, back into the equation to get the derivative in terms of xx only.

More from this chapter

All Continuity and Differentiability solutions →

Solve your own maths question free →