30 і 14√5+√29(14√5+√29-8√5)(14√5+√29-6√5)(14√5+√29-2√29) і це все під корнем

по другому не могу решить, должно быть правильно

2sin x*cos x - sgrt3*sin x - sgrt2*cos x + sgrt3*sgrt2/ 2 = 0; (2 sin x*cos x - sgrt2*cos x) - (sgrt3*sin x - sgrt3/sgrt2)= 0; (sgrt2*sgrt2*cos x - sgrt2*cosx) - (sgrt3*sinx - sgrt3/sgrt2)=0; sgrt2*cosx(sgrt2*sinx - 1) - sgrt3(sin x - 1/sgrt2)=0; sgrt2*cosx(sgrt2*sinx - 1) - sgrt3/sgrt2(sgrt2*sin x - 1)=0; (sgrt2*sin x - 1)(sgrt2*cos x - sgrt3/sgrt2)=0; 1) sgrt2*sinx - 1 = 0;   sin x = 1/sgrt2; sin x = sgrt2/2; x = (-1)^k * pi/4 + pi*k; k-z 2) sgrt2*cos x - sgrt3/ sgrt2= 0; cosx = sgrt3/2; x = + - pi/3 + 2 pi*k; k-z

Объяснение:

a_1+5d=4\\a_{11}=a_1+10d\\\\S_{11}=\frac{a_1+a_1+10d}{2}*11=\frac{2a_1+10d}{2}*11=\frac{2(a_1+5d)}{2}*11=\frac{2*4}{2}*11=44" class="latex-formula" id="TexFormula2" src="https://tex.z-dn.net/?f=S_%7B11%7D%3D%5Cfrac%7Ba_1%2Ba_%7B11%7D%7D%7B2%7D%2A11%5C%5C%5C%5Ca_6%3D4%5C%5Ca_6%3Da_1%2B5d%3D%3Ea_1%2B5d%3D4%5C%5Ca_%7B11%7D%3Da_1%2B10d%5C%5C%5C%5CS_%7B11%7D%3D%5Cfrac%7Ba_1%2Ba_1%2B10d%7D%7B2%7D%2A11%3D%5Cfrac%7B2a_1%2B10d%7D%7B2%7D%2A11%3D%5Cfrac%7B2%28a_1%2B5d%29%7D%7B2%7D%2A11%3D%5Cfrac%7B2%2A4%7D%7B2%7D%2A11%3D44" title="S_{11}=\frac{a_1+a_{11}}{2}*11\\\\a_6=4\\a_6=a_1+5d=>a_1+5d=4\\a_{11}=a_1+10d\\\\S_{11}=\frac{a_1+a_1+10d}{2}*11=\frac{2a_1+10d}{2}*11=\frac{2(a_1+5d)}{2}*11=\frac{2*4}{2}*11=44">