How would you verify the identity?
sin^1/2x-cosx-sin^5/2xcosx=cos^3xradsinx
6 answers
what is rad?
radical
multiply both sides by the sqrt sinx
sinx-cosxsinx-sin^3x cosx=cos^3x sinx
sinx-cosxsinx-(1-cos^2x)sinxcosx=
sinx(1-cosx)-sinxcosx+sinxcox^3x=
sinx(1-cosx-cosx)+sinx cox^3x=
Hmmm. This is telling me the identity does not exist, because sinx(1-2cosx) is not zero.
check my work. There has to be an error here, but I am certain this is (was ) leading somewhere.
sinx-cosxsinx-sin^3x cosx=cos^3x sinx
sinx-cosxsinx-(1-cos^2x)sinxcosx=
sinx(1-cosx)-sinxcosx+sinxcox^3x=
sinx(1-cosx-cosx)+sinx cox^3x=
Hmmm. This is telling me the identity does not exist, because sinx(1-2cosx) is not zero.
check my work. There has to be an error here, but I am certain this is (was ) leading somewhere.
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.
(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.
Thanks, Reiny.
I think I have the same book as you Crystal... I have no clue how to solve this thing... :p
1 answer