Problem

Solve for the exact solutions in the interval $[0,2 \pi)$. If the equation has no solutions, respond with DNE. $2 \sec ^{2}(x)=3-\tan (x)$ Calculator

Solution

Step 1 :\(2\sec^2(x) = 3 - \tan(x)\)

Step 2 :Rewrite \(\sec^2(x)\) as \(1 + \tan^2(x)\)

Step 3 :\(2(1 + \tan^2(x)) = 3 - \tan(x)\)

Step 4 :Simplify to get \(2\tan^2(x) - \tan(x) + 2 = 3\)

Step 5 :Subtract 3 from both sides to get \(2\tan^2(x) - \tan(x) - 1 = 0\)

Step 6 :This is a quadratic equation in terms of \(\tan(x)\). Solve it using the quadratic formula

Step 7 :\(\tan(x) = \frac{-(-1) \pm \sqrt{(-1)^2 - 4*2*(-1)}}{2*2}\)

Step 8 :Solving this gives \(\tan(x) = \frac{1 \pm \sqrt{9}}{4}\)

Step 9 :So, \(\tan(x) = \frac{1 \pm 3}{4}\)

Step 10 :This gives two possible solutions for \(\tan(x)\): \(\tan(x) = 1\) and \(\tan(x) = -0.5\)

Step 11 :For \(\tan(x) = 1\), \(x = \frac{\pi}{4}\) and \(x = \frac{5\pi}{4}\)

Step 12 :For \(\tan(x) = -0.5\), \(x = \arctan(-0.5)\) and \(x = \pi + \arctan(-0.5)\)

Step 13 :Using a calculator, we find that \(\arctan(-0.5) \approx -0.4636\). Adding \(\pi\) to this gives \(\approx 2.6779\)

Step 14 :\(\boxed{x = \frac{\pi}{4}, x = \frac{5\pi}{4}, x \approx -0.4636, x \approx 2.6779}\)

From Solvely APP
Source: https://solvelyapp.com/problems/GQtlM6GTEW/

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