<span>1/tg</span>²<span>x+1/Sinx+3=0
cos²x/sin²x + 1/sinx + 3 = 0</span>
<span>(cos</span>²<span>x
+ sinx + 3sin</span>²<span>x) / sin²x = 0,</span>
<span> sin
^2x ≠ 0, x ≠ </span>πk, k∈<span>Z; </span><span>
1 - <span> sin </span></span>²<span><span>x +
sinx + 3sin</span></span>²<span><span>x = 0
</span></span>2sin²x + sinx + 1 = 0
D < 0, решений нет
Такие графики на картиночке....
3) =-2*√(9*0,02)=-2*3√0,02=-6√0,02
4)=4/9*√9*7= 4/9 *3√7=4/3√7
5)=3/7*√49*2=3/7*7*√2=3√2
6) =10*√0,01*3=10*0,1√3=√3
Sin57cos27+cos57sin27= sin(57 + 27) = sin(84) ≈ 0.99
sin57cos27-cos57sin27= sin(57 - 27) = sin(30) = 1/2
2sin 75*cos75= sin2*75 = sin150 = sin(180 - 30) = sin30 = 1/2
2sin 75 - cos75 = 2si + 45) – cos(30 + 45) = 2sin30cos45 + 2cos30sin45 – cos30cos45 + sin30sin45 = 2*(1/2)*(√2/2) + 2*(√3/2)*(√2/2) - (√3/2)*(√2/2) + (1/2)* (√2/2) = 3√2/4<span> - √6/4</span>
Tg105=tg(60+45)=(tg60+tg45)/(1-tg60tg45)=(1+√3)/(1-√3)=(1+√3)²/(1-√3)(1+√3)=
=(4+√3)/(1-3)=-(4+√3)/2