Решение:
1\medskip\\7^1\leq 7^{\cos^2 x+1}\leq 7^2,~|-7\medskip\\0\leq 7^{\cos^2 x+1}-7\leq 42\Leftrightarrow 0\leq y\leq 42 \Rightarrow E(y)=\left[0;42\right]" alt="-1\leq\cos x\leq 1,\medskip\\0\leq\cos^2 x\leq 1,~|+1\medskip\\1\leq\cos^2 x+1\leq 2,~|\, 7>1\medskip\\7^1\leq 7^{\cos^2 x+1}\leq 7^2,~|-7\medskip\\0\leq 7^{\cos^2 x+1}-7\leq 42\Leftrightarrow 0\leq y\leq 42 \Rightarrow E(y)=\left[0;42\right]" align="absmiddle" class="latex-formula">
Ответ.