Question #40454

1 Answer
Dec 26, 2017

#2 cos (x+15°) + 3 sin (x+15°)= 1.8#

#=>2/sqrt13 cos (x+15°) + 3/sqrt13 sin (x+15°)= 1.8/sqrt13#

Taking #cosalpha=2/sqrt13 and sinalpha=3/sqrt13#
So
#tanalpha=3/2=>alpha=tan^-1(3/2) =56.3^@#

#=>cosalphacos (x+15°) + sinalpha sin (x+15°)= 1.8/sqrt13#
#=>cos (x+15°-alpha)= 1.8/sqrt13#

#=>cos (x+15°-56.3^@)= 1.8/sqrt13=cos60^@#

#=>x=60^@+56.3^@-15^@=101.3^@#