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Let y=f(x)=4x^(3)+2x-6, then the value ...

Let `y=f(x)=4x^(3)+2x-6`, then the value of `int_(0)^(2)f(x)dx+int_(0)^(30)f^(-1)(y)dy` is equal to __________.

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To solve the problem, we need to evaluate the expression: \[ \int_{0}^{2} f(x) \, dx + \int_{0}^{30} f^{-1}(y) \, dy \] where \( f(x) = 4x^3 + 2x - 6 \). ### Step 1: Calculate \( \int_{0}^{2} f(x) \, dx \) First, we need to compute the integral of \( f(x) \) from 0 to 2. \[ \int_{0}^{2} (4x^3 + 2x - 6) \, dx \] We can integrate each term separately: \[ \int 4x^3 \, dx = \frac{4}{4} x^4 = x^4 \] \[ \int 2x \, dx = x^2 \] \[ \int -6 \, dx = -6x \] Now, we can combine these results: \[ \int (4x^3 + 2x - 6) \, dx = x^4 + x^2 - 6x \] Now we evaluate this from 0 to 2: \[ \left[ x^4 + x^2 - 6x \right]_{0}^{2} = \left[ 2^4 + 2^2 - 6 \cdot 2 \right] - \left[ 0^4 + 0^2 - 6 \cdot 0 \right] \] Calculating the upper limit: \[ = 16 + 4 - 12 = 8 \] The lower limit is 0, so: \[ \int_{0}^{2} f(x) \, dx = 8 \] ### Step 2: Find \( f^{-1}(y) \) and calculate \( \int_{0}^{30} f^{-1}(y) \, dy \) To find \( f^{-1}(y) \), we need to find the values of \( x \) such that \( f(x) = y \). First, we need to find \( f(1) \) and \( f(2) \): \[ f(1) = 4(1)^3 + 2(1) - 6 = 4 + 2 - 6 = 0 \quad \Rightarrow \quad f^{-1}(0) = 1 \] \[ f(2) = 4(2)^3 + 2(2) - 6 = 32 + 4 - 6 = 30 \quad \Rightarrow \quad f^{-1}(30) = 2 \] Now we can change the variable in the second integral: Using the substitution \( y = f(t) \), we have \( dy = f'(t) \, dt \). The limits change from \( y = 0 \) to \( y = 30 \), which corresponds to \( t = 1 \) to \( t = 2 \). Thus, we can rewrite the integral: \[ \int_{0}^{30} f^{-1}(y) \, dy = \int_{1}^{2} t \cdot f'(t) \, dt \] Now we calculate \( f'(t) \): \[ f'(x) = 12x^2 + 2 \] So the integral becomes: \[ \int_{1}^{2} t (12t^2 + 2) \, dt = \int_{1}^{2} (12t^3 + 2t) \, dt \] Integrating term by term: \[ \int 12t^3 \, dt = 3t^4 \] \[ \int 2t \, dt = t^2 \] Thus, \[ \int (12t^3 + 2t) \, dt = 3t^4 + t^2 \] Evaluating from 1 to 2: \[ \left[ 3t^4 + t^2 \right]_{1}^{2} = \left[ 3(2^4) + (2^2) \right] - \left[ 3(1^4) + (1^2) \right] \] \[ = \left[ 3(16) + 4 \right] - \left[ 3(1) + 1 \right] = (48 + 4) - (3 + 1) = 52 - 4 = 48 \] ### Step 3: Combine the results Now we can combine the results of both integrals: \[ \int_{0}^{2} f(x) \, dx + \int_{0}^{30} f^{-1}(y) \, dy = 8 + 48 = 56 \] Thus, the final answer is: \[ \boxed{56} \]
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