Math Problem Statement

cosec -7pi/6

Solution

To find csc(7π6)\csc\left(-\frac{7\pi}{6}\right), we proceed as follows:

Step 1: Recognize the angle

The cosecant function is the reciprocal of sine, so: csc(θ)=1sin(θ)\csc(\theta) = \frac{1}{\sin(\theta)}

Step 2: Simplify the angle

We simplify the given angle 7π6-\frac{7\pi}{6} by adding 2π2\pi (since the sine function is periodic with period 2π2\pi):

7π6+2π=7π6+12π6=5π6-\frac{7\pi}{6} + 2\pi = -\frac{7\pi}{6} + \frac{12\pi}{6} = \frac{5\pi}{6}

So, csc(7π6)=csc(5π6)\csc\left(-\frac{7\pi}{6}\right) = \csc\left(\frac{5\pi}{6}\right).

Step 3: Find the sine of 5π6\frac{5\pi}{6}

The angle 5π6\frac{5\pi}{6} is in the second quadrant, where sine is positive. The reference angle is π6\frac{\pi}{6}, and we know: sin(5π6)=sin(π6)=12\sin\left(\frac{5\pi}{6}\right) = \sin\left(\frac{\pi}{6}\right) = \frac{1}{2}

Step 4: Find cosecant

Since csc(θ)=1sin(θ)\csc(\theta) = \frac{1}{\sin(\theta)}, we have: csc(5π6)=112=2\csc\left(\frac{5\pi}{6}\right) = \frac{1}{\frac{1}{2}} = 2

Thus, csc(7π6)=2\csc\left(-\frac{7\pi}{6}\right) = 2.

Would you like more details, or do you have any questions?

Here are 5 related questions:

  1. What is csc(π3)\csc\left(-\frac{\pi}{3}\right)?
  2. How do you calculate sin(5π4)\sin\left(-\frac{5\pi}{4}\right)?
  3. What is the period of the cosecant function?
  4. How do you find the reference angle for 7π6-\frac{7\pi}{6}?
  5. Can you explain how the reciprocal identities apply to trigonometric functions?

Tip: For negative angles, always try to simplify by adding 2π2\pi to convert them to positive angles within a standard range.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Cosecant Function
Angle Simplification

Formulas

csc(θ) = 1/sin(θ)
Angle Periodicity: θ + 2π
sin(π/6) = 1/2

Theorems

Reciprocal Identity of Cosecant
Periodic Property of Trigonometric Functions

Suitable Grade Level

Grades 10-12