Saurabh Koranglekar
Last Activity: 6 Years ago
To solve the equation \((\sec \theta - \tan \theta) / (\sec \theta + \tan \theta) = 36 / 49\), we first need to simplify the expression and find the required quantity \((\csc \theta - \sec \theta) / (\csc \theta + \sec \theta)\). Let's break this down step by step.
Understanding the Initial Equation
We start with the equation:
\((\sec \theta - \tan \theta) / (\sec \theta + \tan \theta) = 36 / 49\)
Recall that:
- \(\sec \theta = \frac{1}{\cos \theta}\)
- \(\tan \theta = \frac{\sin \theta}{\cos \theta}\)
Substituting these definitions into our expression gives us:
\((\frac{1}{\cos \theta} - \frac{\sin \theta}{\cos \theta}) / (\frac{1}{\cos \theta} + \frac{\sin \theta}{\cos \theta})\)
This simplifies to:
\((1 - \sin \theta) / (1 + \sin \theta)\)
Setting Up the Proportions
Now, let's set this equal to \(36 / 49\):
\(\frac{1 - \sin \theta}{1 + \sin \theta} = \frac{36}{49}\)
Cross-multiplying results in:
49(1 - \sin \theta) = 36(1 + \sin \theta)
Distributing gives:
49 - 49\sin \theta = 36 + 36\sin \theta
Now, rearranging terms leads to:
49 - 36 = 49\sin \theta + 36\sin \theta
Thus:
13 = 85\sin \theta
From which we find:
\(\sin \theta = \frac{13}{85}\)
Finding Cosecant and Secant Values
Next, we need to calculate \((\csc \theta - \sec \theta) / (\csc \theta + \sec \theta)\). First, we need to find \(\csc \theta\) and \(\sec \theta\):
\(\csc \theta = \frac{1}{\sin \theta} = \frac{85}{13}\)
\(\sec \theta = \frac{1}{\cos \theta}\)
To find \(\cos \theta\), we can use the Pythagorean identity:
\(\sin^2 \theta + \cos^2 \theta = 1\)
Calculating \(\cos^2 \theta\):
\(\cos^2 \theta = 1 - \left(\frac{13}{85}\right)^2 = 1 - \frac{169}{7225} = \frac{7225 - 169}{7225} = \frac{7056}{7225}\)
Thus, \(\cos \theta = \sqrt{\frac{7056}{7225}} = \frac{84}{85}\).
Now we can find \(\sec \theta\):
\(\sec \theta = \frac{1}{\cos \theta} = \frac{85}{84}\)
Putting It All Together
Now substituting \(\csc \theta\) and \(\sec \theta\) into the expression:
\(\frac{\csc \theta - \sec \theta}{\csc \theta + \sec \theta} = \frac{\frac{85}{13} - \frac{85}{84}}{\frac{85}{13} + \frac{85}{84}}\)
Finding a common denominator for the numerators and denominators:
The common denominator of 13 and 84 is 1092. Thus:
Numerator: \(\frac{85 \times 84 - 85 \times 13}{1092} = \frac{7140 - 1105}{1092} = \frac{6035}{1092}\)
Denominator: \(\frac{85 \times 84 + 85 \times 13}{1092} = \frac{7140 + 1105}{1092} = \frac{8245}{1092}\)
Finally, simplifying gives:
\(\frac{6035}{8245}\), which can be reduced to \(\frac{13}{17}\) after finding the GCD.
The Final Answer
Therefore, the value of \((\csc \theta - \sec \theta) / (\csc \theta + \sec \theta)\) is:
\(\frac{13}{17}\)