unit circle MCQ Questions for Class 12

Simple Explanation

क्योंकि \(\sin\frac{\pi}{3}=\frac{\sqrt{3}}{2}\) और \(\sin^{-1}x\) का principal मान क्षेत्र \([-\frac{\pi}{2},\,\frac{\pi}{2}]\) है, अतः \(\sin^{-1}\!\left(\frac{\sqrt{3}}{2}\right)=\frac{\pi}{3}\)। विकल्प -\(\frac{\pi}{3}\) गलत है क्योंकि \(\sin(-\frac{\pi}{3})=-\frac{\sqrt{3}}{2}\)। \(\frac{\pi}{6}\) और \(\frac{\pi}{4}\) के साइन क्रमशः \(\frac{1}{2}\) और \(\frac{\sqrt{2}}{2}\) होते हैं, इसलिए वे उपयुक्त नहीं हैं। परीक्षा सुझाव: सामान्य कोणों के \(\sin,\cos\) मान याद रखें। / Since \(\sin\frac{\pi}{3}=\frac{\sqrt{3}}{2}\) and the principal value of \(\sin^{-1}x\) lies in \([-\frac{\pi}{2},\frac{\pi}{2}]\), we have \(\sin^{-1}\!\left(\frac{\sqrt{3}}{2}\right)=\frac{\pi}{3}\). The option \(-\frac{\pi}{3}\) is incorrect because \(\sin(-\frac{\pi}{3})=-\frac{\sqrt{3}}{2}\). \(\frac{\pi}{6}\) and \(\frac{\pi}{4}\) are wrong as their sines are \(\frac{1}{2}\) and \(\frac{\sqrt{2}}{2}\) respectively. Exam tip: memorize standard sine/cosine values for common angles (0, \(\frac{\pi}{6}\), \(\frac{\pi}{4}\), \(\frac{\pi}{3}\), \(\frac{\pi}{2}\)).