For a positive constant aa find dydx\frac{d y}{d x}, where y=ai+1t, and x=(t+1t)ay=a^{i+\frac{1}{t}} \text {, and } x=\left(t+\frac{1}{t}\right)^a

Answer: dydx=at+1tln⁡aa(t+1t)a−1\frac{d y}{d x} = \frac{a^{t+\frac{1}{t}} \ln a}{a\left(t+\frac{1}{t}\right)^{a-1}}

Step-by-step solution

Step 1: Differentiate y with respect to t

We need to find dydx\frac{dy}{dx}. Since both yy and xx are functions of tt, we can use the chain rule: dydx=dydt⋅dtdx\frac{dy}{dx} = \frac{dy}{dt} \cdot \frac{dt}{dx}. First, let's differentiate yy with respect to tt. We use the formula for differentiating bf(t)b^{f(t)}, which is bf(t)ln⁡b⋅f′(t)b^{f(t)} \ln b \cdot f'(t). Here, b=ab=a and f(t)=t+1tf(t) = t + \frac{1}{t}. The derivative of t+1tt + \frac{1}{t} is 1−1t21 - \frac{1}{t^2}.

Step 2: Differentiate x with respect to t

Next, we differentiate xx with respect to tt. We use the chain rule for differentiating uau^a, where u=t+1tu = t + \frac{1}{t}. The derivative is aua−1⋅dudta u^{a-1} \cdot \frac{du}{dt}. So, we get a(t+1t)a−1a\left(t+\frac{1}{t}\right)^{a-1} multiplied by the derivative of t+1tt + \frac{1}{t}, which is 1−1t21 - \frac{1}{t^2}.

Step 3: Find dt/dx

Since we need dtdx\frac{dt}{dx} for the chain rule, we take the reciprocal of dxdt\frac{dx}{dt}.

Step 4: Apply the Chain Rule

Now we multiply dydt\frac{dy}{dt} by dtdx\frac{dt}{dx} to find dydx\frac{dy}{dx}. We substitute the expressions we found in the previous steps.

Step 5: Simplify the expression

We can cancel out the common term (1−1t2)\left(1 - \frac{1}{t^2}\right) from the numerator and the denominator, assuming t≠±1t \neq \pm 1. This leaves us with the simplified expression for dydx\frac{dy}{dx}.

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