Can you multiply the double angle forumla?

[musiclover55]

Homework Statement

I have sin4x, can I use the double angle forumla and make it 4sinxcosx?

Homework Equations

double angle forumla

The Attempt at a Solution

sin4x----> 4sinxcosx

 

[zyj]

...try graphing both and see if they're the same.

 

[Mark44]

Homework Statement

I have sin4x, can I use the double angle forumla and make it 4sinxcosx?

In a word, no.
The double-angle formula says that sin(2A) = 2*sin(A)cos(A).

When you use formulas, you need to be very careful to follow the pattern being used.
If you write sin(4x) as sin(2(2x)), you can use the double-angle formula, replacing A in the above by 2x.

Homework Equations

double angle forumla

The Attempt at a Solution

sin4x----> 4sinxcosx