√49^3=√(7^2)^3=√7^6=√((7)^3)^2=7^3=49*7=343
<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
1/7x-15=1/4x-3
-3/28x-12=0