Identify Function: We need to find the derivative of the function (sin(x))/(cos(x)) with respect to x. This is a quotient, so we will use the quotient rule for differentiation. The quotient rule states that if we have a function h(x)=f(x)/g(x), then its derivative h′(x) is given by (f′(x)g(x)−f(x)g′(x))/(g(x))2. Here, f(x)=sin(x) and g(x)=cos(x).
Apply Quotient Rule: First, we differentiate f(x)=sin(x) with respect to x. The derivative of sin(x) is cos(x). So, f′(x)=cos(x).
Differentiate sin(x): Next, we differentiate g(x)=cos(x) with respect to x. The derivative of cos(x) is −sin(x). So, g′(x)=−sin(x).
Differentiate cos(x): Now we apply the quotient rule. We have f′(x)=cos(x) and g′(x)=−sin(x), so we plug these into the quotient rule formula: h′(x)=(cos(x)⋅cos(x)−sin(x)⋅(−sin(x)))/(cos(x))2.
Plug into Quotient Rule: Simplify the expression in the numerator: cos(x)⋅cos(x)−sin(x)⋅(−sin(x))=cos2(x)+sin2(x).
Simplify Numerator: We know from the Pythagorean identity that cos2(x)+sin2(x)=1. So, the numerator simplifies to 1.
Apply Pythagorean Identity: Now we have h′(x)=(cos(x))21. We can also write this as h′(x)=sec2(x), since sec(x) is the reciprocal of cos(x).
Final Derivative: Therefore, the derivative of cos(x)sin(x) with respect to x is sec2(x).
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