# fp3 hyperbolic functions (a standard question that you've probably seen 100 times)Watch

#1
Using the definitions of sinhx and coshx, prove that

sinh(A-B) = sinhAcoshB - coshAsinhB

my working:

consider LHS: sinh(A-B) = (e^(A-B) - e^(B-A))/2

= (1/2)[(e^A)(e^-B) - (e^B)(e^-A)]

don't really know where to go from here, any help would be appreciated. thanks in advance
0
7 years ago
#2
See what you make of it if you try with the RHS first.
0
7 years ago
#3
Yes, as a general rule, it's easier to start from the "more complicated side" (since things will probably cancel to get you towards the simpler side).
0
7 years ago
#4
(Original post by olipal)
See what you make of it if you try with the RHS first.
This.

If you do the LHS then it's hard to see the cancelling down that would happen if you did the RHS first.
0
#5
i'll attempt with the RHS first after i finish this other question. thanks
0
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