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tan(a)/1-cot(a)+cot(a)/1-tan(a)
prove = tan(a)+cot(a)+1

2007-01-14 18:35:30 · 6 answers · asked by Anonymous in Science & Mathematics Mathematics

6 answers

multiply first fraction by sin/sin and second by cos/cos [on left], and turn tan into sin/cos and cot into cos/sin. get

(sin²/cos)/(sin - cos) + (cos²/sin)/(cos - sin)

reverse sign of 2nd fraction and order of 2nd denominator, get

(sin²/cos)/(sin - cos) - (cos²/sin)/(sin - cos)

add tops, get

[ sin²/cos - cos²/sin] / (sin - cos)

add top and get

[(sin^3 - cos^3) / (sin cos)] / (sin - cos)

factor top

[(sin - cos)(sin² + sin cos + cos²)/(sin cos)] / (sin - cos)

cancel common (sin - cos)

(sin² + sin cos + cos²) / (sin cos)

and now divide through

sin/cos + 1 + cos/sin = tan + 1 + cot

2007-01-14 19:33:09 · answer #1 · answered by Philo 7 · 0 0

Prove the identity.

tan(a)/(1-cot(a)) + cot(a)/(1-tan(a)) = tan(a)+cot(a)+1

Let's work with the left hand side.

tan(a)/(1-cot(a)) + cot(a)/(1-tan(a))
= (sin a/cos a)/(1 - cos a/sin a) + (cos a/sin a)/(1 - sin a/cos a)
= (sin² a/cos a)/(sin a - cos a) + (cos² a/sin a)/(cos a - sin a)
= (sin² a/cos a)/(sin a - cos a) - (cos² a/sin a)/(sin a - cos a)
= {(sin² a/cos a) - (cos² a/sin a)}/(sin a - cos a)
= (sin³ a - cos³ a)/{(sin a)(cos a)(sin a - cos a)}
= (sin a - cos a)(sin² a + (sin a)(cos a) + cos² a)
/{(sin a)(cos a)(sin a - cos a)}
= (sin² a + (sin a)(cos a) + cos² a)/{(sin a)(cos a)}
= (sin a/cos a) + 1 + (cos a/sin a)
= tan a + 1 + cot a
= tan(a) + cot(a) + 1 = right hand side

2007-01-15 03:06:44 · answer #2 · answered by Northstar 7 · 0 1

write first term as tan^2(a)/tan(a)-1 by putting cot(a)=1/tan(a)
we get the final expression as cot(a)-tan^2(a)/1-tan(a)
which can be written as 1-tan^3(a)/tan(a){1-tan(a)}
1-tan^3(a) is expanded as {1-tan(a)}{1+tan(a)+tan^2(a)}
divide this by denominator i.e. tan(a){1-tan(a)}
we get answer as
tan(a)+cot(a)+1

2007-01-15 02:46:08 · answer #3 · answered by WhItE_HoLe 3 · 0 0

this should do it. for the top equation, add the two fractions together using a common denominator, then split up the fraction, then simplify. remember, when working with trig identities, you cannot cross the equal sign. in other words, you can't set them equal to each other, and then solve. you must solve to prove they are equal to each other.

2007-01-15 02:46:45 · answer #4 · answered by J J 3 · 0 0

Part of your question got cut off.

2007-01-15 02:45:33 · answer #5 · answered by Phineas Bogg 6 · 0 0

ohh

2007-01-18 22:52:47 · answer #6 · answered by Anonymous · 0 0

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