Posted by Crystal on Thursday, February 12, 2009 at 10:04pm.
How would you verify the identity?
sin^1/2xcosxsin^5/2xcosx=cos^3xradsinx

PreCal (verifying trig identities)  bobpursley, Thursday, February 12, 2009 at 10:12pm
what is rad?

PreCal (verifying trig identities)  Crystal, Thursday, February 12, 2009 at 10:14pm
radical

thinking needed  bobpursley, Thursday, February 12, 2009 at 10:31pm
multiply both sides by the sqrt sinx
sinxcosxsinxsin^3x cosx=cos^3x sinx
sinxcosxsinx(1cos^2x)sinxcosx=
sinx(1cosx)sinxcosx+sinxcox^3x=
sinx(1cosxcosx)+sinx cox^3x=
Hmmm. This is telling me the identity does not exist, because sinx(12cosx) is not zero.
check my work. There has to be an error here, but I am certain this is (was ) leading somewhere. 
PreCal (verifying trig identities)  Reiny, Thursday, February 12, 2009 at 10:38pm
I read your identity as
(sinx)^(1/2)  cosx  (sinx)^(5/2)*cosx = (cosx)^3 *(sinx)^(1/2)
I picked 30 degrees, and the
left side was NOT equal to the right side.
So the way you typed it, it is not an identity. 
PreCal (verifying trig identities)  bobpursley, Thursday, February 12, 2009 at 10:48pm
Thanks, Reiny.

PreCal (verifying trig identities)  John, Monday, February 8, 2010 at 9:59am
I think I have the same book as you Crystal... I have no clue how to solve this thing... :p