# I am stuck and need help...

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Posted by SERGIO on November 04, 2002 at 21:02:03:

Hi I sure need some help in finishing these...

Question 9.b).

Given that sin 55deg = .819 and cos 20deg = .94
Show how you would use the identities for sin (A+B) nd cos (A+B) to find the followingcos 35
= cos (55 - 20)

= (cos 55) (cos 20) + (sin 55) (sin20)

Question 9.c).

Given that sin 55deg = .819 and cos 20deg = .94
Show how you would use the identities for sin (A+B) nd cos (A+B) to find the followingcos 35
= tan (A-B)
= tan A- tan B
-------------
1+tan A tan B

Question 10. b).

Prove that

sin x cos x 1
------------- + ------------- = -------
sin x + cos x sin x - cos x sin^2 x-1

(please note that when I put ^2, I am trying to say that there is a small 2 above the sin. Kind of like the squared symbol).

Any help will be greatly appreciated...
Thanks,
SERG...

• Sorry... SERGIO 21:07:55 11/04/02 (0)
• OOPS SERGIO 21:04:46 11/04/02 (0)

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