Math, asked by sandhansahu303, 1 month ago

find me the answer plz​

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Answered by kv44489
2

Answer:

the value of theta = 45°

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Answered by MissSolitary
1

—› Solution :-

 \implies  \tt \: 3 \: tan(  \theta -  {15}^{0}) = tan( \theta +  {15}^{0} )

 \implies \tt \:  \frac{3}{1}  =  \frac{tan( \theta +  {15}^{0}) }{tan( \theta -  {15}^{0}) }  \\

We know that,

According to componendo and dividendo,

 \boxed{ \gray {\sf \:  \frac{a}{b}  =  \frac{c}{d}  \implies \frac{a + b}{a - b} =  \frac{c + d}{c - d} }  }\\

 \implies \tt \:  \frac{3 + 1}{3 - 1}  =  \frac{tan( \theta  +   {15}^{0} ) + tan( \theta -  {15}^{0}) }{tan( \theta +  {15}^{0} ) - tan( \theta -  {15}^{0}) } \\

 \implies \tt \:  \frac{ \cancel4 \: {}^{2} }{ \cancel2}  =  \frac{tan( \theta  +   {15}^{0} ) + tan( \theta -  {15}^{0}) }{tan( \theta +  {15}^{0} ) - tan( \theta -  {15}^{0}) } \\

 \implies \tt \:  2=  \frac{tan( \theta  +   {15}^{0} ) + tan( \theta -  {15}^{0}) }{tan( \theta +  {15}^{0} ) - tan( \theta -  {15}^{0}) } \\

We know that,

 \boxed{ \gray {\sf \: tan \: \theta   =  \frac{sin \: \theta}{cos \: \theta} } }\\

 \implies \tt \: 2 =  \frac{ \:  \:  \:  \:  \frac{sin(\theta +  {15}^{0}) }{cos(\theta +  {15}^{0} )}  +  \frac{sin(\theta  -   {15}^{0})}{cos(\theta  -   {15}^{0})}  \:  \:  \:  \: }{  \frac{sin(\theta +  {15}^{0})}{cos(\theta +  {15}^{0})} -  \frac{sin(\theta  -   {15}^{0})}{cos(\theta  -  {15}^{0})}  }  \\  \\

 \tt \implies \:  2 =  \frac{ \:  \:  \:  \:  \frac{sin(\theta +  {15}^{0}).cos(\theta  - {15}^{0}) + sin(\theta - {15}^{0}).cos(\theta +  {15}^{0})}{cos(\theta +  {15}^{0}).cos(\theta  -   {15}^{0})} \:  \:  \:  \:  }{ \frac{sin(\theta +  {15}^{0}).cos(\theta  - {15}^{0})  -  sin(\theta - {15}^{0}).cos(\theta +  {15}^{0})}{cos(\theta +  {15}^{0}).cos(\theta  -   {15}^{0})} }  \\  \\

 \tt \implies \:  2 =  \frac{ \:  \:  \:  \:  \frac{sin(\theta +  {15}^{0}).cos(\theta  - {15}^{0}) + sin(\theta - {15}^{0}).cos(\theta +  {15}^{0})}{ \cancel{cos(\theta +  {15}^{0})}. \cancel{cos(\theta  -   {15}^{0})}} \:  \:  \:  \:  }{ \frac{sin(\theta +  {15}^{0}).cos(\theta  - {15}^{0})  -  sin(\theta - {15}^{0}).cos(\theta +  {15}^{0})}{ \cancel{cos(\theta +  {15}^{0})}. \cancel{cos(\theta  -   {15}^{0})}} }  \\  \\

 \tt \implies \:  2 =  \frac{sin(\theta +  {15}^{0}).cos(\theta  - {15}^{0}) + sin(\theta - {15}^{0}).cos(\theta +  {15}^{0})}{sin(\theta +  {15}^{0}).cos(\theta  - {15}^{0})  -  sin(\theta - {15}^{0}).cos(\theta +  {15}^{0})}  \\  \\

We know that,

 \boxed{ \gray {\sf \: sin(A+B) = sinA  \: cosB + cosA  \: sinB} }\\  { \boxed{{\gray{ \sf{sin(A-B) = sinA  \: cosB - cosA  \: sinB}}}}}

so,

 \sf \: sin(\theta + 15°) \:  cos(\theta - 15°) = sinA  \: cosB

therefore,

 \tt \implies \: 2 =  \frac{sin((\theta +  {15}^{0} ) + (\theta -  {15}^{0} ))}{sin((\theta  + {15}^{0} ) - (\theta -  {15}^{0}) }  \\  \\

 \tt \implies \: 2 =  \frac{sin(\theta +  {15}^{0} + \theta -  {15}^{0} )}{sin(\theta  + {15}^{0} - \theta -  {15}^{0}) }  \\  \\

 \tt \implies \: 2 =  \frac{sin(\theta +  \cancel{ {15}^{0} }+ \theta -   \cancel{{15}^{0} })}{sin( \cancel{\theta } + {15}^{0} -  \cancel{\theta} -  {15}^{0}) }  \\  \\

 \tt \implies \: 2 =  \frac{sin(2 \theta)}{sin \:  {30}^{0} }  \\

 \tt \implies \: 2 =  \frac{ \: sin  \: 2\theta}{ \frac{1}{2} }  \\

 \tt \implies \: 2 = 2 \: sin \: 2 \theta

 \tt \implies \:  \frac{ \cancel{2}}{ \cancel{2}}  = sin \: 2 \theta

 \tt \implies \: 1 = sin \: 2 \theta

We know that,

sin 90° = 1

 \tt \implies \: 2 \theta =  {90}^{0}

  \tt \implies \theta =  \frac{  \:  \:  \:  \:  \:  \:  { \cancel{90} {}^{0} } \: ^{45} }{ \cancel2}  \\  \\  \boxed{ \red{ \tt \implies \theta \:  =  {45}^{0} }}

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