If cosecx + cotx = 2, then cosecx = ?
1.25
Let's solve the given trigonometric equation to find the value of $\text{cosec}x$. We are given the equation:
$\text{cosec}x + \text{cot}x = 2$
We need to find the value of $\text{cosec}x$. To do this, we can use a fundamental trigonometric identity that relates $\text{cosec}x$ and $\text{cot}x$. The identity is:
$\text{cosec}^2x - \text{cot}^2x = 1$
This identity is in the form of a difference of squares, $a^2 - b^2 = (a-b)(a+b)$. Applying this to the identity, we get:
$(\text{cosec}x - \text{cot}x)(\text{cosec}x + \text{cot}x) = 1$
We already know from the problem statement that $\text{cosec}x + \text{cot}x = 2$. We can substitute this value into the factored identity:
$(\text{cosec}x - \text{cot}x)(2) = 1$
Now, we can solve for the term $(\text{cosec}x - \text{cot}x)$:
$\text{cosec}x - \text{cot}x = \frac{1}{2}$
So, we now have a system of two linear equations involving $\text{cosec}x$ and $\text{cot}x$:
To find $\text{cosec}x$, we can add these two equations together. Notice that the $\text{cot}x$ term in the first equation is positive, and in the second equation, it's negative. When we add them, they will cancel out.
Add (Equation 1) and (Equation 2):
$(\text{cosec}x + \text{cot}x) + (\text{cosec}x - \text{cot}x) = 2 + \frac{1}{2}$
Combine like terms:
$\text{cosec}x + \text{cosec}x + \text{cot}x - \text{cot}x = 2 + 0.5$
$2 \times \text{cosec}x = 2.5$
Now, solve for $\text{cosec}x$ by dividing both sides by 2:
$\text{cosec}x = \frac{2.5}{2}$
$\text{cosec}x = 1.25$
Thus, the value of $\text{cosec}x$ is 1.25.
| Concept | Identity/Method | Application Here |
|---|---|---|
| Pythagorean Identity | $\text{cosec}^2\theta - \text{cot}^2\theta = 1$ | Used to find a second equation involving $\text{cosec}x$ and $\text{cot}x$. |
| Difference of Squares | $a^2 - b^2 = (a-b)(a+b)$ | Factored $\text{cosec}^2x - \text{cot}^2x$. |
| Solving System of Linear Equations | Addition or Substitution | Added two equations ($\text{cosec}x + \text{cot}x = 2$ and $\text{cosec}x - \text{cot}x = 0.5$) to eliminate $\text{cot}x$. |
The trigonometric functions $\text{cosec}x$ and $\text{cot}x$ are reciprocals and ratios related to sine and tangent:
Problems like this one often require recognizing and applying these fundamental identities to simplify expressions or solve equations involving trigonometric functions.
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