Résoudre dans R les équations suivantes :
1) sin (x- 2π/3) = sin (π/5)
donc
{x-2π/3=π/5 (2π)
{x-2π/3=π-π/5 (2π)
donc
{x=π/5+2π/3 (2π)
{x=π-π/5 +2π/3(2π)
donc
{x=13π/15 (2π)
{x=22π/15 (2π)
2) cos (3x + π/6) = cos (x+ π/5)
donc
{3x + π/6=x+ π/5 (2π)
{3x + π/6=-x- π/5 (2π)
donc
{2x =π/5-π/6 (2π)
{4x =- π/5-π/6 (2π)
donc
{2x =π/30 (2π)
{4x =- 11π/30 (2π)
donc
{x =π/60 (π)
{x =- 11π/120 (π/2)