hamna_fa Hello !! Does anyone know how to do the question below. I'm pretty sure it has something to do with trig: 1. cos 4A + 1 is equal to: A 2(cos A – 1)2 B 2 cos2 2A C cos2 A D sin 2A E 1 – sin 2A
God Using the double angle formula: (http://www.mathguide.com/lessons2/TrigAngles/daf00.gif) cos(4A) +1 = 2 cos2(2A) - 1 + 1 = 2 cos2(2A) So B!
lovelyherring in the Cambridge textbook ch 3A, Q15... The Fibonacci sequence is defined by F1 = 1, F2 = 1 and Fn+2 = Fn+1 + Fn for n ∈ N. Use the rule to find F3, F4 and F5. Show that Fn+2 = 2Fn + Fn−1 for all n ∈ N. How do you do the 'show' part?
TnGn74 lovelyherring In the new equation we have eliminated F(n+1), so try thinking about what could be substituted there.
lovelyherring TnGn74 ' oh lol I see... so basically you can say that F(n+1) = Fn + F(n-1) and then sub that F(n+1) in the old equation so that: F(n+2) = Fn + F(n-1) +Fn Then simplify and then: F(n+2) = 2Fn + F(n-1)
perilousranch Does anyone know where I can find the solutions for chapter 6 in the Cambridge textbook? When I went to go check the answers it says 'see solutions supplement'. Does anyone know what this is referring to?
