Problem

Find all exact solutions on the interval $[0,2 \pi$ ). Look for opportunities to use trigonometric identities. (Enter your answers as a comma-separated list. If an answer does not exist, enter DNE.)
\[
\sin ^{2}(x)-\cos ^{2}(x)-\sin (x)=0
\]

Answer

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Answer

Final Answer: The solutions to the equation \(\sin ^{2}(x)-\cos ^{2}(x)-\sin (x)=0\) in the interval \([0,2 \pi)\) are \(x = 330^\circ\) and \(x = 90^\circ\). So, the final answer is \(\boxed{330^\circ, 90^\circ}\).

Steps

Step 1 :Given the equation \(\sin ^{2}(x)-\cos ^{2}(x)-\sin (x)=0\).

Step 2 :Use the Pythagorean identity \(\sin^2(x) + \cos^2(x) = 1\) to rewrite the equation as \(\sin^2(x) - (1 - \sin^2(x)) - \sin(x) = 0\).

Step 3 :Simplify the equation to get \(2\sin^2(x) - \sin(x) - 1 = 0\).

Step 4 :This is a quadratic equation in terms of \(\sin(x)\), which can be solved using the quadratic formula to get the solutions \(-1/2\) and \(1\).

Step 5 :Substitute these solutions back into the equation to find the corresponding values of \(x\) in the interval \([0, 2\pi)\). The solutions are \(x = -0.523598775598299 + 2\pi\) and \(x = 1.57079632679490\).

Step 6 :Convert these solutions from radians to degrees to get \(x = 330^\circ\) and \(x = 90^\circ\).

Step 7 :Final Answer: The solutions to the equation \(\sin ^{2}(x)-\cos ^{2}(x)-\sin (x)=0\) in the interval \([0,2 \pi)\) are \(x = 330^\circ\) and \(x = 90^\circ\). So, the final answer is \(\boxed{330^\circ, 90^\circ}\).

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