Math Problem Statement

If f(x)=(cscx)/(tanx) then f^(')(x) is?

Solution

To find the derivative of f(x)=csc(x)tan(x)f(x) = \frac{\csc(x)}{\tan(x)}, we will use the quotient rule for differentiation.

The quotient rule states that if we have a function of the form:

f(x)=g(x)h(x),f(x) = \frac{g(x)}{h(x)},

then its derivative is given by:

f(x)=g(x)h(x)g(x)h(x)[h(x)]2.f'(x) = \frac{g'(x)h(x) - g(x)h'(x)}{[h(x)]^2}.

In this case:

  • g(x)=csc(x)g(x) = \csc(x)
  • h(x)=tan(x)h(x) = \tan(x)

Step 1: Find the derivatives of g(x)g(x) and h(x)h(x):

  1. The derivative of g(x)=csc(x)g(x) = \csc(x) is: g(x)=csc(x)cot(x)g'(x) = -\csc(x) \cot(x)

  2. The derivative of h(x)=tan(x)h(x) = \tan(x) is: h(x)=sec2(x)h'(x) = \sec^2(x)

Step 2: Apply the quotient rule:

f(x)=(csc(x)cot(x))tan(x)csc(x)sec2(x)[tan(x)]2.f'(x) = \frac{(-\csc(x) \cot(x)) \tan(x) - \csc(x) \sec^2(x)}{[\tan(x)]^2}.

Step 3: Simplify the expression:

f(x)=csc(x)cot(x)tan(x)csc(x)sec2(x)tan2(x).f'(x) = \frac{-\csc(x) \cot(x) \tan(x) - \csc(x) \sec^2(x)}{\tan^2(x)}.

Now, let's simplify the terms inside the numerator:

  • Recall that cot(x)=1tan(x)\cot(x) = \frac{1}{\tan(x)}, so: csc(x)cot(x)tan(x)=csc(x).\csc(x) \cot(x) \tan(x) = \csc(x).

Thus, the expression simplifies to:

f(x)=csc(x)csc(x)sec2(x)tan2(x).f'(x) = \frac{-\csc(x) - \csc(x) \sec^2(x)}{\tan^2(x)}.

You can factor out csc(x)-\csc(x) from the numerator:

f(x)=csc(x)(1+sec2(x))tan2(x).f'(x) = \frac{-\csc(x) \left(1 + \sec^2(x)\right)}{\tan^2(x)}.

This is the derivative of f(x)f(x).

Final Answer:

f(x)=csc(x)(1+sec2(x))tan2(x).f'(x) = \frac{-\csc(x) \left(1 + \sec^2(x)\right)}{\tan^2(x)}.

Let me know if you need any further clarification or additional steps!

Follow-up Questions:

  1. Can you explain the quotient rule in more detail with another example?
  2. What is the relationship between csc(x)\csc(x) and sec(x)\sec(x)?
  3. How would the derivative change if the function was f(x)=sin(x)tan(x)f(x) = \frac{\sin(x)}{\tan(x)}?
  4. Can we simplify this derivative further, or is this the most reduced form?
  5. How do we find the critical points of this function from the derivative?

Tip:

When simplifying trigonometric expressions in derivatives, it helps to recall the basic identities like cot(x)=1tan(x)\cot(x) = \frac{1}{\tan(x)} and sec2(x)=1+tan2(x)\sec^2(x) = 1 + \tan^2(x), as they can simplify the terms significantly.

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Math Problem Analysis

Mathematical Concepts

Calculus
Differentiation
Trigonometry
Quotient Rule

Formulas

Quotient Rule: f'(x) = [g'(x)h(x) - g(x)h'(x)] / [h(x)]^2
csc(x) = 1/sin(x)
sec^2(x) = 1 + tan^2(x)

Theorems

Quotient Rule for Differentiation

Suitable Grade Level

Grades 11-12