Question : $7 \sin ^2 A+3 \cos ^2 A=4$, then find $\cot A$:
Option 1: $\sqrt{3}$
Option 2: $\sqrt{2}$
Option 3: $\frac{1}{\sqrt{2}}$
Option 4: $\frac{1}{\sqrt{3}}$
Correct Answer: $\sqrt{3}$
Solution : $7 \sin ^2 A+3 \cos ^2 A=4$ $7 \sin ^2 A+3(1-\sin ^2 A)=4$ $7 \sin ^2 A+3-3 \sin ^2 A=4$ $4 \sin ^2 A=1$ $ \sin ^2 A=\frac{1}{4}$ $ \sin A=\frac{1}{2}$ $\therefore A = 30^{\circ}$ $\cot A = \cot 30^{\circ} = \sqrt3 $ Hence, the correct answer is $\sqrt3$.
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Question : Find the value of $\sqrt{\frac{1-\tan A}{1+\tan A}}$.
Option 1: $\sqrt{\frac{1+\sin 2 A}{\cos 2 A}}$
Option 2: $\sqrt{\frac{1-\sin 2 A}{\cos 2 A}}$
Option 3: $\sqrt{\frac{1+\sin A}{\cos A}}$
Option 4: $\sqrt{\frac{1-\sin A}{\cos A}}$
Question : If $\sin \theta+\cos \theta=\frac{\sqrt{11}}{3}$, then what is $\sin \theta-\cos \theta$?
Option 1: $\frac{\sqrt{7}}{4}$
Option 2: $\frac{\sqrt{7}}{3}$
Option 3: $\frac{\sqrt{5}}{3}$
Option 4: $\frac{\sqrt{5}}{2}$
Question : If $\sin (A-B)=\sin A \cos B–\cos A\sin B$, then $\sin 15°$ will be:
Option 1: $\frac{\sqrt{3}+1}{2\sqrt{2}}$
Option 2: $\frac{\sqrt{3}}{2\sqrt{2}}$
Option 3: $\frac{\sqrt{3}–1}{–\sqrt{2}}$
Option 4: $\frac{\sqrt{3}–1}{2\sqrt{2}}$
Question : If $\sin \theta+\cos \theta=\sqrt{2} \cos \theta$, then find $\frac{\sin \theta-\cos \theta}{\sin \theta}$:
Option 1: $-\sqrt{2}$
Option 2: $-1$
Option 3: $1$
Option 4: $\sqrt{2}$
Question : If $\sin \theta+\cos \theta=\frac{\sqrt{11}}{3}$, then the value of $(\cos \theta-\sin \theta)$ is:
Option 1: $\frac{\sqrt{5}}{3}$
Option 2: $\frac{7}{3}$
Option 3: $\frac{5}{3}$
Option 4: $\frac{\sqrt{7}}{3}$
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