MCQ
$\cos ({\tan ^{ - 1}}x) = $
- A$\sqrt {1 + {x^2}} $
- ✓$\frac{1}{{\sqrt {1 + {x^2}} }}$
- C$1 + {x^2}$
- DNone of these
$\therefore \,\,\cos \theta = \frac{1}{{\sqrt {1 + {{\tan }^2}\theta } }} = \frac{1}{{\sqrt {1 + {x^2}} }}$
Hence $\cos \theta = \cos \,({\tan ^{ - 1}}x) = \frac{1}{{\sqrt {1 + {x^2}} }}$.
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$\frac{3}{48\pi}\text{cm}/\text{sec}.$
$(A)$ $N ^{\top} M N$ is symmetric or skew symmetric, according as $M$ is symmetric or skew symmetric
$(B)$ $M N-N M$ is skew symmetric for all symmetric matrices $M$ and $N$
$(C)$ $M N$ is symetric for all symmetric matrices $M$ and $N$
$(D)$ $(\operatorname{adj} M)(\operatorname{adj} N)=\operatorname{adj}(M N)$ for all invertible matrices $M$ and $N$