Question

if Pn=cosnθ+sinnθ,then Pn-Pn-2 =kPn-4,wherea. k=-1b. k=1c. k=-sin2θcos2θ d. k=4type write answer with correct answer

Answer 1

Answer:

P

n

=cos

n

θ+sin

n

θ

P

n

−P

n−2

=cos

n

θ+sin

n

θ−cos

n−2

θ−sin

n−2

θ=−sin

2

θcos

n−2

θ−cos

2

θsin

n−2

θ=−sin

2

θcos

2

θ(cos

n−4

θ+sin

n−4

θ)

=−sin

2

θcos

2

θP

n−4

k=−sin

2

θcos

2

θ