MCQ
${d \over {dx}}\left( {{1 \over {{x^4}\sec x}}} \right) = $
- A${{x\sin x + 4\cos x} \over {{x^5}}}$
- ✓${{ - (x\sin x + 4\cos x)} \over {{x^5}}}$
- C${{4\cos x - x\sin x} \over {{x^5}}}$
- DNone of these
$ = \frac{{{x^4}( - \sin x) - \cos x(4{x^3})}}{{{{({x^4})}^2}}}$
$ = \frac{{ - {x^3}(x\sin x + 4\cos x)}}{{{x^8}}} = \frac{{ - (x\sin x + 4\cos x)}}{{{x^5}}}$.
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
$x-2 y=1, x-y+k z=-2, k y+4 z=6, k \in R$
consider the following statements :
$(A)$ The system has unique solution if $k \neq 2$, $k \neq-2$
$(B)$ The system has unique solution if $k =-2$.
$(C)$ The system has unique solution if $k =2$.
$(D)$ The system has no-solution if $k =2$.
$(E)$ The system has infinite number of solutions if $k \neq-2$
Which of the following statements are correct?