Posted by Kewal on Friday, December 30, 2011 at 4:52am.
Use the same method as my other proof, but let
(n+1)A = x and
(n+2)A = y
y-x = A
sin(n+1)Asin(n+2)A+cos(n+1)Acos(n+2)A
= sinxsiny + cosxcosy
= cos(y-x) = cosA
Related Questions
Trigonometry - Prove that sin(n+1)Asin(n-1)A + cos(n+1)Acos(n-1)A = cos2A
Trigonometry - I need to prove that the following is true. Thanks. csc^2(A/2)=...
Trigonometry - 1.Solve tan^2x + tan x – 1 = 0 for the principal value(s) to...
trigonometry hlp me - 6.Prove that tan y cos^2 y + sin^2y/sin y = cos y + sin &#...
tigonometry - expres the following as sums and differences of sines or cosines ...
Trigonometry - Prove that 1-cosA+cosB-cos(A+B)/1+cosA-cosB-cos(A+B) = ...
Trigonometry - Prove that cos(A+B)cosC - cos(B+C)cosA = sinBsin(C-A)
Trigonometry - Prove the identity sin(x+y+z)+sin(x+y-z)+sin(x-y+z)+ sin(x-y-z...
Precal - I do not understand how to do this problem ((sin^3 A + cos^3 A)/(sin A...
Math - Calculus - The identity below is significant because it relates 3 ...
For Further Reading
