![image](https://tex.z-dn.net/?f=sin100%5E0%3Dsin%2890%5E0%2B10%5E0%29%5Cin+2%5C%3B+chetvert%5C%3B+%5Cto+%5C%3B+sin100%5E0%3E0%5C%5C%5C%5Ccos300%5E0%3Dcos%28270%5E0%2B30%5E0%29%5Cin+4%5C%3B+chetvert%5C%3B+%5Cto+%5C%3B+cos300%5E0%3E0%5C%5C%5C%5Csin100%5E0%5Ccdot+cos300%5E0%3E0)
0\\\\cos300^0=cos(270^0+30^0)\in 4\; chetvert\; \to \; cos300^0>0\\\\sin100^0\cdot cos300^0>0" alt="sin100^0=sin(90^0+10^0)\in 2\; chetvert\; \to \; sin100^0>0\\\\cos300^0=cos(270^0+30^0)\in 4\; chetvert\; \to \; cos300^0>0\\\\sin100^0\cdot cos300^0>0" align="absmiddle" class="latex-formula">