Chapter 1: Problem 13
If \(\sin ^{2} \theta=\frac{x^{2}+y^{2}+1}{2 x}\), then \(x\) must be (a) \(-3\) (b) \(-2\) (c) 1 (d) None of these
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Chapter 1: Problem 13
If \(\sin ^{2} \theta=\frac{x^{2}+y^{2}+1}{2 x}\), then \(x\) must be (a) \(-3\) (b) \(-2\) (c) 1 (d) None of these
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If \(A B C\) is a triangle such that angle \(A\) is obtuse, then (a) \(\tan B \tan C>1\) (b) \(\tan B \tan C<1\) (c) \(\tan B \tan C=1\) (d) None of theseSolution: (b) Let us take \(\tan A=-\tan (B+C)\) \(\Rightarrow \tan A=\frac{\tan B+\tan C}{\tan B \tan C-1}\) Since \(A\) is obtuse therefore \(\tan B \tan C-1<0\) \(\Rightarrow \tan B \tan C<1\)
If \(A=130^{\circ}\) and \(x=\sin A+\cos A\), then (a) \(x>0\) (b) \(x<0\) (c) \(x=0\) (d) \(x \geq 0\)
\(\sin \frac{9 \pi}{14} \sin \frac{11 \pi}{14} \sin \frac{13 \pi}{14}\) equals (a) \(\frac{1}{64}\) (b) \(-\frac{1}{64}\) (c) \(\frac{1}{8}\) (d) \(\frac{-1}{8}\)
If \(a_{n+1}=\sqrt{\frac{1}{2}\left(1+a_{n}\right)}\) then \(\cos \left(\frac{\sqrt{1-a_{0}^{2}}}{a_{1} a_{2} a_{3} \ldots \ldots . \text { to } \infty}\right)\) is equal to (a) 1 (b) \(-1\) (c) \(a_{0}\) (d) \(1 / a_{0}\)
Which of the following statement(s) is/are correct? (a) \(\sum_{r=1}^{7} \tan ^{2} \frac{r \pi}{16}=\sum_{t=1}^{7} \cot ^{2} \frac{r \pi}{16}=35\) (b) \(\sum_{r=1}^{10} \cos ^{3} \frac{r \pi}{3}=-\frac{9}{8}\) (c) \(\sum_{r=1}^{3} \tan ^{2}\left(\frac{2 r-1}{7}\right)=\sum_{r=1}^{3} \cot ^{2}\left(\frac{2 r-1}{7}\right)\) (d) \(\sum_{r=1}^{3} \tan ^{2}\left(\frac{2 r-1}{7}\right) \cdot \sum_{r=1}^{3} \cot ^{2}\left(\frac{2 r-1}{7}\right)=105\)
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