A alyren Junior Member Joined Sep 9, 2010 Messages 59 Nov 7, 2010 #1 solve each equation on the interval 0<data<2pi cos(2data) - cos (4 data)= 0 no idea how to solve this, first i try using double angle identities : cos(2data) = 2cos^2-1. but what do i need for the cos(4data)?
solve each equation on the interval 0<data<2pi cos(2data) - cos (4 data)= 0 no idea how to solve this, first i try using double angle identities : cos(2data) = 2cos^2-1. but what do i need for the cos(4data)?
D Deleted member 4993 Guest Nov 7, 2010 #2 alyren said: solve each equation on the interval 0<data<2pi cos(2data) - cos (4 data)= 0 no idea how to solve this, first i try using double angle identities : cos(2data) = 2cos^2-1. but what do i need for the cos(4data)? Click to expand... \(\displaystyle cos(4\theta) = 2cos^2(2\theta) - 1\)
alyren said: solve each equation on the interval 0<data<2pi cos(2data) - cos (4 data)= 0 no idea how to solve this, first i try using double angle identities : cos(2data) = 2cos^2-1. but what do i need for the cos(4data)? Click to expand... \(\displaystyle cos(4\theta) = 2cos^2(2\theta) - 1\)
