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Multiple Choice
Find the derivative of each function. y=(3x+5)2
A
3
B
6x
C
9x+15
D
18x+30
Verified step by step guidance
1
Rewrite the function y = (3x + 5)^2 to clearly identify it as a composite function. This is a function of the form f(g(x)), where f(u) = u^2 and g(x) = 3x + 5.
Apply the chain rule to find the derivative of y. The chain rule states that if y = f(g(x)), then dy/dx = f'(g(x)) * g'(x).
First, compute the derivative of the outer function f(u) = u^2 with respect to u. This gives f'(u) = 2u.
Substitute g(x) = 3x + 5 into f'(u). This gives f'(g(x)) = 2(3x + 5).
Now, compute the derivative of the inner function g(x) = 3x + 5 with respect to x. This gives g'(x) = 3. Multiply f'(g(x)) by g'(x) to get the final derivative: dy/dx = 2(3x + 5) * 3.