Math Problem Statement

-8csc(pi/4)cos(pi/6)-cos(pi) show steps please

Solution

To simplify the expression 8csc(π4)cos(π6)cos(π)-8\csc\left(\frac{\pi}{4}\right)\cos\left(\frac{\pi}{6}\right) - \cos(\pi), we'll follow these steps:

Step 1: Calculate csc(π4)\csc\left(\frac{\pi}{4}\right)

The cosecant function is the reciprocal of the sine function:

csc(π4)=1sin(π4)\csc\left(\frac{\pi}{4}\right) = \frac{1}{\sin\left(\frac{\pi}{4}\right)}

Since sin(π4)=22\sin\left(\frac{\pi}{4}\right) = \frac{\sqrt{2}}{2}:

csc(π4)=122=22=2\csc\left(\frac{\pi}{4}\right) = \frac{1}{\frac{\sqrt{2}}{2}} = \frac{2}{\sqrt{2}} = \sqrt{2}

Step 2: Calculate cos(π6)\cos\left(\frac{\pi}{6}\right)

cos(π6)\cos\left(\frac{\pi}{6}\right) is known to be:

cos(π6)=32\cos\left(\frac{\pi}{6}\right) = \frac{\sqrt{3}}{2}

Step 3: Calculate cos(π)\cos(\pi)

The cosine of π\pi is:

cos(π)=1\cos(\pi) = -1

Step 4: Substitute back into the expression

Now we can substitute these values into the original expression:

8csc(π4)cos(π6)cos(π)=8(2)(32)(1)-8\csc\left(\frac{\pi}{4}\right)\cos\left(\frac{\pi}{6}\right) - \cos(\pi) = -8(\sqrt{2})\left(\frac{\sqrt{3}}{2}\right) - (-1)

Step 5: Simplify the expression

Calculating 8(2)(32)-8(\sqrt{2})(\frac{\sqrt{3}}{2}):

8232=46-8 \cdot \frac{\sqrt{2} \cdot \sqrt{3}}{2} = -4\sqrt{6}

Now add the (1)-(-1):

46+1-4\sqrt{6} + 1

Final Result

Thus, the simplified expression is:

1461 - 4\sqrt{6}

If you have any questions or would like more details on any part of the solution, please let me know! Here are some related questions you might find interesting:

  1. What are the values of sin\sin and tan\tan for π4\frac{\pi}{4}?
  2. How do you derive the sine and cosine values for common angles?
  3. What are other trigonometric identities related to cosecant and cosine?
  4. Can you explain the unit circle and its significance in trigonometry?
  5. How would this expression change if the angles were in degrees instead of radians?

Tip: Always remember to review the basic trigonometric ratios for quick reference when simplifying expressions involving trigonometric functions!

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Cosecant
Cosine

Formulas

csc(x) = 1/sin(x)
cos(x) for specific angles

Theorems

Basic trigonometric identities

Suitable Grade Level

Grades 10-12