SOLUTION: verify that is an indentity a) Sin(90 degree+A)=Cos A b) Sin(x-y)=(1-cotx tany)/(csc x sec y)

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Question 507660: verify that is an indentity
a) Sin(90 degree+A)=Cos A
b) Sin(x-y)=(1-cotx tany)/(csc x sec y)
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
I'll do the first one to get you started

a)
sin(90+A) = cos(A)

sin(90)cos(A) + cos(90)sin(A) = cos(A)

(1)cos(A) + (0)sin(A) = cos(A)

cos(A) = cos(A)