4sine(x) + 5kosine(x)=0
4 sine=-5kosine
sine(x)=(-5/4)kosine(x)
sine^2 =(25/16) kosine^2=1.5625 kosine^2
sine^2=1.5625*[1-sine^2(x)]
sine^2(1+1.5625)=1.5625
2.5625 sine^2=1.5625
sine^2(x)=(1.5625/2.5625)=0.609756097
sine(x)=root(0.609....)=0.780868809
invers sine giv x=51.34019175 deg
2y-0.3=51.34019175
2y=51.34...+0.3=51.64019175
y=51.640.../2=25.82009587