- Home
- Standard 11
- Mathematics
3.Trigonometrical Ratios, Functions and Identities
normal
$cosec^2\theta $ = $\frac{4xy}{(x +y)^2}$ is true if and only if
A
$x + y$ $\neq$ $0$
B
$x = y$, $x$ $\neq$ $0$
C
$x = y$
D
$x$ $\neq$ $0$, $y$ $\neq$ $0$
Solution
$\frac{4xy}{(x +y)^2}$ $\leq$ $1$ $\Rightarrow$ $(x – y)^2$ < $0$ $x$= $y$ but $x$ $\neq$ $0$ ($cosec^2\theta$ $\neq$ $0$)
Standard 11
Mathematics
