MCQ
If ${\cos ^{ - 1}}\frac{3}{5} - {\sin ^{ - 1}}\frac{4}{5} = {\cos ^{ - 1}}x,$ then $ x=$
- A$0$
- ✓$1$
- C$-1$
- D$2$
$ \Rightarrow {\cos ^{ - 1}}\frac{3}{5} - {\cos ^{ - 1}}\sqrt {1 - \frac{{16}}{{25}}} = {\cos ^{ - 1}}x$
$ \Rightarrow {\cos ^{ - 1}}\frac{3}{5} - {\cos ^{ - 1}}\frac{3}{5} = {\cos ^{ - 1}}x$
$ \Rightarrow {\cos ^{ - 1}}x = 0 \Rightarrow x = 1$.
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Statement $-1 :$ The probability that the chosen numbers when arranged in some order will form an $A.P.$ is $\frac{1}{{85}}$ .
Statement $-2 :$ If the four chosen numbers form an $A.P.$, then the set of all possible values of common difference is $\left( { \pm 1, \pm 2, \pm 3, \pm 4, \pm 5} \right)$ છે.

$\frac{2}{21}$
$\frac{1}{28}$
$\frac{167}{168}$