Question

if tan theta is equal to cos 20 degrees + sin 20 degrees by cos 20 degrees minus sin 20 degrees .then the value of thetha is​

Answer 1

Step-by-step explanation:

cos20+sin20

cos20−sin20

\frac{cos 20(1- \frac{sin20}{cos20}) }{cos 20(1 + \frac{sin20}{cos20} }

cos20(1+

cos20

sin20

cos20(1−

cos20

sin20

)

\frac{cos 20(1- tan20) }{cos 20(1 + tan20) }

cos20(1+tan20)

cos20(1−tan20)

\frac{1- tan20 }{1 + tan20 }

1+tan20

1−tan20

since, \frac{1- tan\alpha }{1 + tan \alpha }= tan (45 -\alpha)

1+tanα

1−tanα

=tan(45−α)

\frac{1- tan20 }{1 + tan20 }

1+tan20

1−tan20

= Tan(45 - 20) = Tan 25

Hence proved

Answer 2

Answer:See the attached image :-