Question

12sinx + 5cosx +13 = 0

Answer 1

√(12²+5²)=√(144+25)=√169=13
13(12/13*sinx+5/138cosx)=-13
12/13*sinx+5/13*cosx=-1
sin(x+a)=-1
sina=5/13 U cosa=12/13
x+a=-π/2+2πn
x=-a-π/2+2πn,n∈z
x=-arcsin5/13-π/13+2πn,n∈a