1) -(1-sin²x) /(1-cos²x) = -cos²x/sin²x= -ctg²x
2)1+ctg²x= 1/sin²x
3)= tg²x
4)1+tg²x-ctg²x= 1/cos²x-ctg²x
5)sinx-2sinx= -sinx
6)cosx-cosx= 0
7)sin²x*(1-cosx) /(1+cosx) (1-cosx) = sin²x(1-cosx) /sin²x= 1-cosx
8)cos²x(1+sinx) /(1-sinx)(1+sinx) = cos²x(1+sinx) /cos²x= 1+sinx
cos(2п-t) = cos(-t) = cost
1)ctg3=<span>-7.01</span>
<span>ctg5=<span>-0.29</span></span>
<span><span>значит ctg3<ctg5</span></span>
<span><span>2)ctg pi/10=0.88</span></span>
<span><span>ctg 13pi/10=<span>0.97</span></span></span>
<span><span><span>значит ctg pi/10<ctg 13 pi/10</span></span></span>
<span><span><span>3) ctg(-1)=<span>-0.64</span></span></span></span>
<span><span><span><span>ctg(-1.2)=<span>-0.39</span></span></span></span></span>
<span><span><span><span><span>значит ctg(-1)<ctg(-1.2)</span></span></span></span></span>
Ctg t = 1\ tg t = 1 \ 9\40 = 40\9
sin t = tg t \ √(1+tg²t)
sin t = - 40\9 \√(1+ 1600\81) = - 40\9 \ √1681\81 = - 40\9 \ 41\9 = - 40\41
cos t = √(1-sin² t)
cos t = - √(1 - 1600\1681) = - √ 1\1681 = - 1\41