How do you simplify sin(u-v)cosv+cos(u-v)sinvsin(uv)cosv+cos(uv)sinv?

1 Answer
Jun 5, 2018

sinusinu

Explanation:

"using the "color(blue)"addition formulae"using the addition formulae

•color(white)(x)sin(x+-y)=sinxcosy+-cosxsinyxsin(x±y)=sinxcosy±cosxsiny

•color(white)(x)cos(x+-y)=cosxcosy∓sinxsinyxcos(x±y)=cosxcosysinxsiny

•color(white)(x)sin^2x+cos^2x=1xsin2x+cos2x=1

sin(u-v)cosvlarrcolor(red)"first term"sin(uv)cosvfirst term

=(sinucosv-cosusinv)cosv=(sinucosvcosusinv)cosv

=sinucos^2vcancel(-cosucosvsinv)

cos(u-v)sinvlarrcolor(red)"second term"

=(cosucosv+sinusinv)sinv

=cancel(cosucosvsinv)+sinusin^2v

"adding the 2 expansions gives"

sinucos^2v+sinusin^2v

=sinu(cos^2v+sin^2v)=sinu