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H(x) = -x² + 3x + 10

1 Answer

4 votes

Answer:

x = 5 or x = -2 or 3 - 2 x (derivative)

Explanation:

Solve for x over the real numbers:

-x^2 + 3 x + 10 = 0

Multiply both sides by -1:

x^2 - 3 x - 10 = 0

x = (3 ± sqrt((-3)^2 - 4 (-10)))/2 = (3 ± sqrt(9 + 40))/2 = (3 ± sqrt(49))/2:

x = (3 + sqrt(49))/2 or x = (3 - sqrt(49))/2

sqrt(49) = sqrt(7^2) = 7:

x = (3 + 7)/2 or x = (3 - 7)/2

(3 + 7)/2 = 10/2 = 5:

x = 5 or x = (3 - 7)/2

(3 - 7)/2 = -4/2 = -2:

Answer: x = 5 or x = -2

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Find the derivative of the following via implicit differentiation:

d/dx(H(x)) = d/dx(10 + 3 x - x^2)

Using the chain rule, d/dx(H(x)) = ( dH(u))/( du) ( du)/( dx), where u = x and d/( du)(H(u)) = H'(u):

(d/dx(x)) H'(x) = d/dx(10 + 3 x - x^2)

The derivative of x is 1:

1 H'(x) = d/dx(10 + 3 x - x^2)

Differentiate the sum term by term and factor out constants:

H'(x) = d/dx(10) + 3 (d/dx(x)) - d/dx(x^2)

The derivative of 10 is zero:

H'(x) = 3 (d/dx(x)) - d/dx(x^2) + 0

Simplify the expression:

H'(x) = 3 (d/dx(x)) - d/dx(x^2)

The derivative of x is 1:

H'(x) = -(d/dx(x^2)) + 1 3

Use the power rule, d/dx(x^n) = n x^(n - 1), where n = 2.

d/dx(x^2) = 2 x:

H'(x) = 3 - 2 x

Simplify the expression:

Answer: = 3 - 2 x

User Jeet Bhatt
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