<span>A1 3)</span>
<span>sin^2 =1-cos^2 = 1- (-7/25)^2 =(625-49)/625</span>
<span>sin=24/25</span>
<span>A2 3)</span>
<span>cos^2 = 1- sin^2 = 1-(-5/13)^2 = (169-25)/169=144/169</span>
<span>cos= 12/13</span>
<span>tg = sin/cos= -5/13 /12/13 = -5/12</span>
<span>A3 4)</span>
<span>sin^2 = 1-cos^2 = 1-(3/5)^2=1-9/25=16/25</span>
<span>sin = -4/5</span>
<span>(1+tg )/(1+ctg) =1+tg /(1+1/tg) =1+tg /((tg+1)/tg)=tg = sin/cos= (-4/5)/(3/5)=-4/3</span>
<span>A4 3)</span>
<span>(1-sin)(1+sin)-(cos^2 - 5)=(1-sin^2)-(cos^2 - 5)=cos^2-cos^2 + 5= 5</span>