Question

The value of

$\lbrack y\rbrack$ cos$f(y) = \frac{y}{\sqrt{1 - y^{2}}},g(y) = \frac{y}{\sqrt{1 + y^{2}}},$ cos$(fog)(y)$ cos $\frac{y}{\sqrt{1 - y^{2}}}$… cos $\frac{y}{\sqrt{1 + y^{2}}}$ is

• A. 1
• B. $\frac{1 - y^{2}}{\sqrt{1 + y^{2}}}$
• C. $g(x) = 1 + x - \lbrack x\rbrack$
• D. None of these

Answer 1

Answer: (B)

$\frac{1 - y^{2}}{\sqrt{1 + y^{2}}}$

Answer 2

coscos....cos $\frac { x } { 2 ^ { n } }$ = $\frac { \sin \mathrm { x } } { 2 ^ { \mathrm { n } } \sin \left( \frac { \mathrm { x } } { 2 ^ { \mathrm { n } } } \right) }$

by trigonometry

= = $\frac { \sin x } { x }$