Question

Срочно даю доп балы тема тригонометрия

Answer 1

3) tg840⁰ = tg( 4 * 180⁰ + 120⁰) = tg120⁰ = tg(90⁰ + 30⁰) =- Ctg30⁰ = - √3

4) Cos1260⁰ = Cos(3* 360⁰ + 180⁰) = Cos180⁰ = - 1

1) Sin(- 30⁰) - 2tg(- 45⁰) - Cos(- 60⁰) = - Sin 30⁰ + 2tg 45⁰ - Cos 60⁰ =

= - 1/2 + 2 * 1 - 1/2 = - 1 + 2 = 1

$2)2tg(-\frac{\pi }{3})*Ctg(-\frac{\pi }{6})+Sin(-\pi)+5Sin^{2}(-\frac{\pi }{3} )=\\\\=-2tg\frac{\pi }{3}*(-Ctg\frac{\pi }{6})-Sin\pi+5Sin^{2}\frac{\pi }{3}=-2*\sqrt{3}*(-\sqrt{3})-0+5*(\frac{\sqrt{3} }{2})^{2}=\\\\=2*3+5*\frac{3}{4} =6+3,75=\boxed{9,75}$