Math, asked by Anonymous, 8 months ago

Proof :

1/1+ sin theta + 1/1-sin theta = 2 sec square theta

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Answers

Answered by niceanish
1

Step-by-step explanation:

1/(1-sintheta) + 1/(1+sintheta)

= (1+sintheta+1-sintheta)/(1+sintheta)(1-sintheta)

=2/1-sin²theta

=2/cos²theta = 2sec²theta

Answered by MohakBiswas
8

\bf\large\blue{Question\::-}

\text{Proof that :}

 \frac{1}{1 +   \: \sin \theta}  +  \frac{1}{1 -   \: \sin \theta}  = 2  \: { \sec}^{2}  \theta

\bf\large\blue{Solution\::-}

 \underline{L.H.S}

 \frac{1}{1 +   \: \sin \theta}  +  \frac{1}{1 -   \: \sin \theta}  = 2  \: { \sec}^{2}  \theta

 =  \frac{1 \:  - \:   \cancel{ \sin \theta } + \:   1    \: +  \:  \cancel{ \sin \theta}}{(1 \:  + \:   \sin \theta )(1  \: -   \: \sin \theta)}

 =  \frac{2}{1 - { \sin }^{2} \theta }

\text{We know, }1 - { \sin}^{2} \theta = {\cos}^{2}\theta

\text{Then,}

 \frac{2}{ { \cos}^{2}  \theta}

 =  \frac{2}{ \frac{1}{ \sec ^{2}  \theta} }

 = 2 \:  \sec ^{2}  \theta \:  = R.H.S

\bf\large\blue{Hence \: proved \:.}

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Hope it helps you :-) ❤️

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