Question

give me anwer please fast​

Answer 1

$\large\pink{\boxed{\boxed{\blue{\underline{\underline{\texttt{ Formulas Used }}}}}}}$

$\large\bf{ → \: {sin}^{2} \theta + {cos}^{2} \theta = 1 }$

$\large\bf{ → \: {cosec}^{2} \theta - {cot}^{2} \theta = 1 }$

$\large\bf{ → \: sin \theta = \frac{1}{cosec\theta} }$

_____________________

$\large\pink{\boxed{\boxed{\blue{\underline{\underline{\star{\texttt{ \: Solution : - }}}}}}}}$

$\large\bf{ ( {cos}^{2} A - 1)( {cot}^{2} A + 1)}$

Now, by using formulas...

$\large\bf{→( - {sin}^{2} A )( {cosec}^{2} A )}$

$\large\bf{→ - \frac{ {sin}^{2}A}{ {sin}^{2} A} }$

$\large\bf{→ - 1 } \: \: \large\green{\bf{Answer!!}}$

So, (b) -1 is the correct option.

Answer 2

$(cos {}^{2} A - 1).( {cot}^{2} + 1) \\ \\ = ( - {sin}^{2} A)( {cosec}^{2} A) \\ \\ = \frac{ - {sin}^{2} A}{sin {}^{2} A} \\ \\ = - 1$