Math Problem Statement

For f, of, x, equals, sine, xf(x)=sinx , minus, start fraction, pi, divided by, 2, end fraction, is less than or equal to, x, is less than or equal to, start fraction, pi, divided by, 2, end fraction− 2 π ​ ≤x≤ 2 π ​ , g, of, x, equals, cosine, xg(x)=cosx , 0, is less than or equal to, x, is less than or equal to, pi0≤x≤π , and h, of, x, equals, tangent, xh(x)=tanx , minus, start fraction, pi, divided by, 2, end fraction, is less than, x, is less than, start fraction, pi, divided by, 2, end fraction− 2 π ​ <x< 2 π ​ , find the exact value of the composite function.

g, to the power minus 1 , left parenthesis, f, of, minus, start fraction, pi, divided by, 4, end fraction, right parenthesisg −1 (f(− 4 π ​ ))

Simplify your answer. Type an exact answer, using radicals as needed. Type an exact answer, using piπ as needed. Use integers or fractions for any numbers in the expression.

Solution

We are tasked with finding the exact value of the composite function g1(f(π4))g^{-1}(f(-\frac{\pi}{4})).

Step 1: Evaluate f(π4)f(-\frac{\pi}{4})

We are given the function: f(x)=sin(x)f(x) = \sin(x) Now, substitute x=π4x = -\frac{\pi}{4} into the sine function: f(π4)=sin(π4)f\left(-\frac{\pi}{4}\right) = \sin\left(-\frac{\pi}{4}\right) Using the identity sin(θ)=sin(θ)\sin(-\theta) = -\sin(\theta), we know that: sin(π4)=sin(π4)=22\sin\left(-\frac{\pi}{4}\right) = -\sin\left(\frac{\pi}{4}\right) = -\frac{\sqrt{2}}{2} Thus: f(π4)=22f\left(-\frac{\pi}{4}\right) = -\frac{\sqrt{2}}{2}

Step 2: Solve for g1(f(π4))=g1(22)g^{-1}(f(-\frac{\pi}{4})) = g^{-1}\left(-\frac{\sqrt{2}}{2}\right)

We are given the function: g(x)=cos(x)g(x) = \cos(x) Now, we need to find the inverse function, g1(y)g^{-1}(y), such that g(g1(y))=yg(g^{-1}(y)) = y. This means we are looking for xx such that: cos(x)=22\cos(x) = -\frac{\sqrt{2}}{2} We know that cos(x)=22\cos(x) = -\frac{\sqrt{2}}{2} at x=3π4x = \frac{3\pi}{4}, within the interval 0xπ0 \leq x \leq \pi.

Thus: g1(22)=3π4g^{-1}\left(-\frac{\sqrt{2}}{2}\right) = \frac{3\pi}{4}

Final Answer:

The exact value of g1(f(π4))g^{-1}(f(-\frac{\pi}{4})) is: 3π4\frac{3\pi}{4}

Would you like more details on any steps?

Here are five related questions:

  1. How do we determine the inverse of a trigonometric function?
  2. What is the domain and range of cos(x)\cos(x) within 0xπ0 \leq x \leq \pi?
  3. How do we find the exact value of trigonometric functions at specific angles?
  4. What is the significance of the interval restrictions for xx in trigonometric functions?
  5. How do we use trigonometric identities to simplify expressions?

Tip: Always check the domain of the function and its inverse to ensure you're using the correct range for inverse trigonometric values.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Inverse Functions
Composite Functions

Formulas

sin(x), cos(x), tan(x)
Inverse cosine: g⁻¹(y) where cos(g⁻¹(y)) = y
Composite function: g⁻¹(f(x))

Theorems

Trigonometric identities: sin(-θ) = -sin(θ)
Cosine inverse function g⁻¹(y) within 0 ≤ x ≤ π

Suitable Grade Level

Grades 11-12