Math, asked by alizaaish864, 9 months ago


(11) If tan a = x +1 and tan B = x - 1, then prove that : 2 cot (a - b) = x square


Answers

Answered by BrainlyIAS
38

Answer

2 cot (a - b) = x²

Given

\bullet \;\; \rm tan\ a=x+1\\\\\bullet \;\; \rm tan\ b=x-1

To Prove

\bullet \;\; \rm 2\ cot(a-b)=x^2

Formula Applied

\bullet \;\; \rm tan(x-y)=\dfrac{tan\ x-tan\ y}{1+tan\ x.tan\ y}\\\\\bullet \;\; \rm (x+y)(x-y)=x^2-y^2\\\\\bullet \;\; \rm tan\ x=\dfrac{1}{cot\ x}

Solution

\rm tan(a-b)=\dfrac{tan\ a-tan\ b}{1+tan\ a.tan\ b}\\\\\to\ \rm tan(a-b)=\dfrac{(x+1)-(x-1)}{1+(x+1)(x-1)}\\\\\to\ \rm tan(a-b)=\dfrac{2}{1+x^2-1}\\\\\to\ \rm tan(a-b)=\dfrac{2}{x^2}\\\\\to\ \rm \dfrac{1}{cot(a-b)}=\dfrac{2}{x^2}\\\\\to\ \rm x^2=2\ cot(a-b)\\\\\to\ \rm 2\ cot(a-b)=x^2\ \bigstar \\\\\to\ \rm Hence\ proved


amitkumar44481: Great :-)
Answered by BrainlyNisha001
29

\huge\mathfrak\blue{Answer:-}

 <font color = white >

Given ,

tanA = x + 1

tanB = x - 1

Now, We know that;

 \tan(a - b)  =  \frac{ \tan \: a -  \tan \: b  }{1 +  \tan \: a \:  \tan \: b}  \\  \tan(a - b)  =  \frac{(x + 1) - (x - 1)}{1 + (x - 1)(x + 1)} \\   \tan(a - b)  =  \frac{x + 1 - x + 1}{1 + ( {x}^{2} - 1)}  \\  \tan(a - b)  =  \frac{2}{1 +  {x}^{2} - 1 }  \\  \tan(a - b)  =  \frac{2}{ {x}^{2} }

We know that ,

 \cot(a - b)  =  \frac{1}{ \tan(a - b)} \\  \cot(a - b)   =  \frac{1}{ \frac{2}{ {x}^{2} } }  \\  \cot(a - b)  =  \frac{ {x}^{2} }{2}  \\ 2 \cot(a - b)  =  {x}^{2}

Hence proved.✌️☺️

1. \:   \tan(a - b) =  \frac{ \tan \: a -  \tan \: b}{1 +  \tan \: a \tan \: b }  \\ 2. \:  \cot \: 0 =  \frac{1}{ \tan \: 0} \\ 3. \: (a + b)(a - b) =  {a}^{2}  -  {b}^{2}

____________________♡

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