Friday

August 22, 2014

August 22, 2014

Posted by **Evelina** on Saturday, November 12, 2011 at 9:06am.

1) 1 + sina*cosa / (cosa + sina)^2 =

2) sina + cosa / 1- 2sin^2a =

- trig -
**Reiny**, Saturday, November 12, 2011 at 9:27amAre you sure the first one isn't

( 1 + 2sina cosa)/(cosa + sina)^2 ?

because then it would be

= (sin^2a + cos^2a + 2sina cosa)/(cosa + sina)^2

= (sina + cosa)^2/(cosa + sina)^2

= 1

2nd:

(sina + cosa)/(1 - 2sin^2a)= (sina + cosa)/(sin^2a + cos^2a - 2sin^2a)

= sina+cosa)/( cos^2a - sin^2a)

= (sina + cosa)/( cosa - sina)(cosa+sina) )

= 1/(cosa - sina)

- trig -
**Evelina**, Saturday, November 12, 2011 at 9:37amoh yes, I wrote the first one wrong.

THANK YOU

**Related Questions**

Maths - Hi, can someone give me the answer to this question: secA-tanA=1/4. Find...

further mathematics - Let P=(cosA sinA) (sinA cosA) Q=(cosB sinA) (sinB cosA) ...

trig - I need to count this: a) 1-tg^2a/1+ctg^2a, when sina =2/3 b) 1-tg^2a/1-...

trig - prove that :cosA-sinA+1/cosA+sinA-1=cosecA+cotA

trig - Prove : (sinA-cosA+1)/(sinA+cosA-1) = (1+sinA)/cosA

maths(trigonometry) - prove that sinA-cosA+1/sinA+cosA-1=1/secA-tanA

trig - How to do this one? (sina/1-cosa) + (1-cosa/sina) = Also, wanted to ask ...

Math - CosA/1+sinA=1-sinA/cosA I have to prove the identity each side has to b ...

Math - prove that sinA/(1+cosA) + (1+cosA)/(sinA) = 2cosecA

math (trig) - i have some problems doing trig the first one is: Show that cos(x/...