Question

Use the half angle formula to solve (sin(4x))^4

Answer 1

No equals sign --> nothing to solve.

Answer 2

But here's some formulas if you'd like to make some substitutions.
http://tutorial.math.lamar.edu/pdf/Trig_Cheat_Sheet.pdf

Answer 3

Use the half angle formula to solve
(Sin(4x))^2=________-1/2cos(_________x)+1/8cos(16x)

Answer 4

Its basically to fill in the blank in the question

Answer 5

Plz i need some help to fill in the blank spaces

Answer 6

Sin² a = ( 1 - cos2a ) / 2

Answer 7

is it sin(4x)^2 or sin(4x)^4?

Answer 8

sin(4x)^4

My appologise

Answer 9

Chlorophyll........so how do i use this formula u presented to solve the question

Answer 10

Sin²(4x) or sin^4 (4x) ?

Answer 11

(sin(4x))^4

Answer 12

I still have the trouble to understand the question, but I'm thinking:
Use the half angle formula to solve
(Sin(4x))^2=________-1/2cos(_________x)+1/8cos(16x)

Answer 13

This is going to require a couple applications of these two identities:
\[\sin(2 \theta)=2\sin(\theta)\cos(\theta)\]
\[\sin^2(\theta)=\frac{1}{2}(1-\cos(\theta))\]

Answer 14

(Sin(4x))^4=________-1/2cos(_________x)+1/8cos(16x)

Answer 15

its raise to the power of 4 not 2..........plz

Answer 16

Yes, that's why you have to use those identities twice.

Answer 17

Though there are also what are called power-reducing identities, which might be more direct. Either way it's going to get a little messy.
Gimme a second to find the power-reducing identity for sine..

Answer 18

OK, this will probably line up more directly with what you're doing:
\[\sin^4(\theta)=\frac{3-4\cos(2 \theta)+\cos(4 \theta)}{8}\]
Just replace Θ with 4x.

Answer 19

(source: http://en.wikipedia.org/wiki/List_of_trigonometric_identities#Power-reduction_formula )

Answer 20

@CliffSedge I have no idea about the existence of formula, but it works nicely :)

Answer 21

Yeah, I usually forget they exist and have to derive them fresh each time from the few I can remember. It's a pain in the neck.

Answer 22

it sure is

Answer 23

put i appreciate the help

Answer 24

n.p. Maybe some other time you can try deriving that power-reducing formula from the half-angle and double-angle identities just to exercise your algebra. ;-)

Answer 25

Yeah MAYBE