Question

cos x + 3sen x = 1 ecuaciones trigonometricas​

Answer 1

$\boxed{\cos \: x + 3 sen \: x = 1}$

$\sqrt{1 - sen {}^{2} x + 3sen \: x \: = 1} \\ \boxed{ \pink{ { \sqrt{1 - sen \: {}^{2}x = 1 - 3 \: sen \: x}} } }$

Elevar al cuadrado

$\boxed {\green{ \large{( \sqrt{1 - sen {}^{2} x} ) {}^{2} = (1 - 3 \: sen \: x) {}^{2} }}}$

$1 \: sen {}^{2} x = 1 - 6sen \: x + 9sen {}^{2} x$

ordenar términos

$10sen {}^{2} x - 6sen \: x = 0$

Factorizar

$senx = 0 \: y \: senx = \frac{6}{10} = \frac{3}{5}$

Resultado

$\boxed{x = 0° \: y \: x = 36°52'11,63,"}$

espero esté bien y te ayude..