Question #2bde7

1 Answer
Jim G.
Nov 20, 2017

#"see explanation"#

Explanation:

#"using the "color(blue)"trigonometric identities"#

#•color(white)(x)sin(A+B)=sinAcosB+cosAsinB#

#•color(white)(x)cos(A+B)=cosAcosB-sinAsinB#

#•color(white)(x)sin^2A+cos^2A=1#

#"consider LHS"#

#cosu(cosucosv-sinusinv)+sinu(sinucosv+cosusinv)#

#=cos^2ucosvcancel(-cosusinusinv)+sin^2ucosvcancel(+sinucosusinv)#

#=cosv(sin^2u+cos^2u)#

#=cosv="RHS"rArr" proven"#

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