Math, asked by khandelwalpranam431, 9 days ago

X = If tan 9° = - then, the value of sec281 /1 + cot2 81 is :​

Answers

Answered by amitnrw
2

Given : tan 9° = x/y

To Find : Sec²81° /(1 + cot²81°)

Solution:

Sec²81° /(1 + cot²81°)

cotx = cosx/sinx

= Sec²81° /(1 + cos²81°/sin²81°)

= sin²81°Sec²81°/( sin²81° +  cos²81°)

sin²x + cos²x = 1

= sin²81°Sec²81°

secx = 1/cosx

= sin²81°/cos²81°

sinx/cosx = tanx

= tan²81°

tan (90° - x) = cotx

= cot²9°

cotx = 1/tanx

= 1/tan²9°

= 1/(x/y)²

= y²/x²

Sec²81° /(1 + cot²81°) = y²/x²

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Answered by vaibhav13550
1

Answer:

Sec²81° /(1+ cot2²81°)

cotx = cosx/sinx

= Sec²81° /(1 + cos²81%/sin²81°)

= sin²81°Sec²81/( sin²81° + cos²81°)

=

sin^2 x + cos^2 x = 1

= sin²81°Sec²81°

secx = 1/cosx

= sin²81%/cos²81°

sinx/cosx = tanx

= tan²81°

tan (90° - x) = cotx

= cot²9°

cotx = 1/tanx

= 1/tan²9°

= 1/(x/y)²

= y²/x²

Sec²81° /(1+ cot²81°) = y²/x².

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