Seudónimo Seudónimo
  • 06-08-2014
  • Mathematics
contestada

cos^2 2x−cos^2 6x=sin4x sin8x
please help me prove it

Respuesta :

Everest2017
Everest2017 Everest2017
  • 06-08-2014
Cos² 2x = (1+cos 4x )/2
cos² 6x  = (1+cos 12x)/2
subtract to get  1/2 (cos 4x - cos 12x )   
=  1/2 (2 sin  4x sin 8x )       as cos A - cos B =  2 [ sin (A+B)/2  sin (A-B)/2 ]
so the answer
Answer Link

Otras preguntas

According to cicero in on duties, all good things in life come from maintaining one's' what
Write an equation in slope-intercept form of the line that passes through the given point and is parallel to the graph of the given equation (-2,3) ; y= 1/2x-1
Vanessa deposited money into a bank account that earned 1.25% simple interest each year. After 1/2 year, she had earned $5.00 in interest on the account. If no
Can someone please help me out?
What was a major effect of the growth of the Ottoman Empire?
What was the land like in the Indus Valley?
What is 30% as a decimal in its simplest form
Which sentence uses the correct pronouns? Grandpa and I share a birthday, so he is exactly 50 years older than me. Grandpa and I share a birthday, so he is exac
Find The last two digit of 36^2015
Which of the following is an example of adapting messages to others? a. attending a sign language class b. a student reading a passage to the class c. a counsel