Double angles : 2 questions (1 Viewer)

[ugotkeys]

1)
Simplify:
2 (cos^2 3x) - 1

2)
Prove following identities:
Sin A + Cos A Tan B =Tan (A+B)
_________________

Cos A - Sin A Tan B

Cheers if you can help

 

[nightweaver066]

3U topic.

1. cos2A = 2cos^2 A -1
Use that.

2. Divide LHS numerator and denominator by cosx.

 

[ugotkeys]

Thanks bro

 

[HeroicPandas]

this is 3U

 

[Kostie100]

3U topic.

1. cos2A = 2cos^2 A -1
Use that.

2. Divide LHS numerator and denominator by cosx.

Hey is it alright if you show the solution for this... I'm having a few problems (probably cause i haven't touched trig in months )

 

[nightweaver066]

Hey is it alright if you show the solution for this... I'm having a few problems (probably cause i haven't touched trig in months )