help me please???

[clumsy29]

..:?:...can you answer this proving identities?

i been dedicate my whole time for these...
please help me guys...

1.sin(A-B)=cos(π/2 + B -A)

2. cot 2θ = (cot^2 θ -1)/(2cotθ)


please help me...

 

[JeffM]

..:?:...can you answer this proving identities?

i been dedicate my whole time for these...
please help me guys...

1.sin(A-B)=cos(π/2 + B -A)

2. cot 2θ = (cot^2 θ -1)/(2cotθ)


please help me...

It is very hard to show where you are getting stuck in your work if you do not show it.

Do you know what \(\displaystyle sin(A - B) = \)?

How about \(\displaystyle cos(\frac{\pi}{2} - C)\)

Do either of those seem to be helpful?

 

[JeffM]

..:?:...can you answer this proving identities?

i been dedicate my whole time for these...
please help me guys...

1.sin(A-B)=cos(π/2 + B -A)

2. cot 2θ = (cot^2 θ -1)/(2cotθ)


please help me...

Here are two hints for your second problem.

What is the relationship between tangent and co-tangent?

What is the double angle formula for the tangent?