Math Problem Statement

Find the exact value of the expression: sec(π/4) + 9 csc(π/6). Do not use a calculator. Simplify your answer.

Solution

The problem you provided asks to find the exact value of the following expression:

sec(π4)+9csc(π6)\sec\left(\frac{\pi}{4}\right) + 9 \csc\left(\frac{\pi}{6}\right)

Let's solve this step-by-step.

Step 1: Evaluate sec(π4)\sec\left(\frac{\pi}{4}\right)

We know that:

sec(θ)=1cos(θ)\sec(\theta) = \frac{1}{\cos(\theta)}

For θ=π4\theta = \frac{\pi}{4}:

cos(π4)=22\cos\left(\frac{\pi}{4}\right) = \frac{\sqrt{2}}{2}

So:

sec(π4)=122=2\sec\left(\frac{\pi}{4}\right) = \frac{1}{\frac{\sqrt{2}}{2}} = \sqrt{2}

Step 2: Evaluate csc(π6)\csc\left(\frac{\pi}{6}\right)

We know that:

csc(θ)=1sin(θ)\csc(\theta) = \frac{1}{\sin(\theta)}

For θ=π6\theta = \frac{\pi}{6}:

sin(π6)=12\sin\left(\frac{\pi}{6}\right) = \frac{1}{2}

So:

csc(π6)=112=2\csc\left(\frac{\pi}{6}\right) = \frac{1}{\frac{1}{2}} = 2

Step 3: Put it all together

Now substitute these values into the original expression:

sec(π4)+9csc(π6)=2+9(2)\sec\left(\frac{\pi}{4}\right) + 9 \csc\left(\frac{\pi}{6}\right) = \sqrt{2} + 9(2)

Simplifying:

=2+18= \sqrt{2} + 18

So, the exact value of the expression is:

2+18\boxed{\sqrt{2} + 18}

Let me know if you'd like any further clarification!


Related Questions:

  1. What are the values of sec(θ)\sec(\theta) and csc(θ)\csc(\theta) for other common angles?
  2. How do you derive trigonometric identities involving secant and cosecant?
  3. What are the exact values for all trigonometric functions at π4\frac{\pi}{4} and π6\frac{\pi}{6}?
  4. How can you use the unit circle to verify these trigonometric function values?
  5. Can you explain how to simplify expressions involving radicals, like 2\sqrt{2}?

Tip:

For exact trigonometric values, try memorizing the sine, cosine, and tangent for key angles such as 00, π6\frac{\pi}{6}, π4\frac{\pi}{4}, π3\frac{\pi}{3}, and π2\frac{\pi}{2}.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Secant
Cosecant
Exact Values

Formulas

sec(θ) = 1/cos(θ)
csc(θ) = 1/sin(θ)

Theorems

Unit Circle Values
Basic Trigonometric Identities

Suitable Grade Level

Grades 9-12