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[tex]1)8^{\frac{2}{3} } -3*9^{\frac{2}{3} } *5^{0} \\\\2)\sqrt[4]{9+\sqrt{65} } *\sqrt[4]{9-\sqrt{65} } \\\\3)cos93^{0} *cos33^{0} +sin93^{0} *sin33^{0}[/tex]
[tex]1)8^{\frac{2}{3} } -3*9^{\frac{2}{3} } *5^{0} \\\\2)\sqrt[4]{9+\sqrt{65} } *\sqrt[4]{9-\sqrt{65} } \\\\3)cos93^{0} *cos33^{0} +sin93^{0} *sin33^{0}[/tex]
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Ответ:
Объяснение:
1) 8^(2/3)-3*9^(2/3)*5⁰=4-3*3∛3=4-9∛3
5⁰=1
8^(2/3)=(∛8)²=2²=4
9^(2/3)=(∛9)²=∛81=∛(3*27)=3∛3
2) (9+√65)^(1/4)*(9-√65)^(1/4)=((9+√65)(9-√65))^(1/4)=
=(81-65)^(1/4)=16^(1/4)=2
3) cos(a-b)=cosacosb+sinasinb
cos93*cos33+sin93*sin33=cos(93-33)=cos60=1/2