Q. Let g(x)=sin(x)cos(x).Find g′(x).Choose 1 answer:(A) sin2(x)sin2(x)−cos2(x)(B) sin2(x)1(C) −sin2(x)1(D) sin2(x)cos2(x)−sin2(x)
Recognize Quotient Rule: Recognize that g(x)=sin(x)cos(x) is a quotient of two functions, so we will use the quotient rule to find its derivative. The quotient rule states that if h(x)=g(x)f(x), then h′(x)=(g(x))2f′(x)g(x)−f(x)g′(x).
Identify Functions: Identify the functions f(x) and g(x) where f(x)=cos(x) and g(x)=sin(x). We will need to find the derivatives f′(x) and g′(x).
Find f′(x): Find the derivative of f(x)=cos(x). The derivative of cos(x) with respect to x is −sin(x). So, f′(x)=−sin(x).
Find g′(x): Find the derivative of g(x)=sin(x). The derivative of sin(x) with respect to x is cos(x). So, g′(x)=cos(x).
Apply Quotient Rule: Apply the quotient rule. Using the derivatives from steps 3 and 4, we get: g′(x)=(sin(x))2−sin(x)⋅sin(x)−cos(x)⋅cos(x).
Simplify Expression: Simplify the expression. We can use the Pythagorean identity sin2(x)+cos2(x)=1 to simplify the numerator:g′(x)=(−sin2(x)−cos2(x))/(sin(x))2=−(sin2(x)+cos2(x))/(sin(x))2=−(1)/(sin(x))2.
Recognize Final Answer: Recognize that −(1)/(sin(x))2 is the same as −(1)/(sin2(x)), which matches answer choice (C).
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