sin ^4 a+cos^4 a+2sin ²a ×cos ²a Question sin ^4 a+cos^4 a+2sin ²a ×cos ²a in progress 0 Môn Toán Khánh Gia 4 years 2020-10-14T23:08:42+00:00 2020-10-14T23:08:42+00:00 1 Answers 98 views 0
Answers ( )
Đáp án:
1
Giải thích các bước giải:
\(\begin{array}{l}
{\sin ^4}a + {\cos ^4}a + 2{\sin ^2}a.{\cos ^2}a\\
= {\left( {{{\sin }^2}a} \right)^2} + 2{\sin ^2}a.{\cos ^2}a + {\left( {{{\cos }^2}a} \right)^2}\\
= {\left( {{{\sin }^2}a + {{\cos }^2}a} \right)^2} = 1
\end{array}\)