Differentiate axa^{x} w.r.t. xx, where aa is a positive constant.

Answer: ddx(ax)=axln⁡a\frac{d}{dx}(a^x) = a^x \ln a

Step-by-step solution

Step 1: Rewrite the expression using base e

To differentiate axa^x, it's often helpful to rewrite it using the natural exponential function ee. We know that any positive number NN can be written as eln⁡Ne^{\ln N}. Applying this property, we can express axa^x as eln⁡(ax)e^{\ln(a^x)}.

Step 2: Simplify the exponent

Using the logarithm property ln⁡(MP)=Pln⁡M\ln(M^P) = P \ln M, we can simplify the exponent. Here, M=aM = a and P=xP = x, so ln⁡(ax)\ln(a^x) becomes xln⁡ax \ln a.

Step 3: Differentiate using the chain rule

Now we differentiate exln⁡ae^{x \ln a} with respect to xx. We use the chain rule, which states that ddx(ef(x))=ef(x)⋅f′(x)\frac{d}{dx}(e^{f(x)}) = e^{f(x)} \cdot f'(x). Here, f(x)=xln⁡af(x) = x \ln a.

Step 4: Differentiate the exponent

Since aa is a positive constant, ln⁡a\ln a is also a constant. The derivative of xx multiplied by a constant is simply that constant. Therefore, the derivative of xln⁡ax \ln a with respect to xx is ln⁡a\ln a.

Step 5: Substitute back and simplify

Substitute the derivative of the exponent back into the chain rule result. We know that exln⁡ae^{x \ln a} is equivalent to axa^x. Therefore, the derivative of axa^x is axln⁡aa^x \ln a.

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