<span><u> 36 </u> + <u> 88 </u> - <u> 4 </u> =
</span>5 - √7 <span>7+√ 5</span> √7 +√5
= <u> </u><u> 36(5 + </u><span><u>√7) </u> + <u> 88</u></span><span><u>(7-√ 5) </u> - <u> 4</u></span><span><u>(√7- √5) </u> =
</span> (5 - √7) (5+ √7) (7+√ 5)(7-√ 5) (√7 +√5)(√7- √5)
= <u> </u><u> 36(5 + </u><span><u>√7) </u> + <u> 88</u></span><span><u>(7-√ 5) </u> - <u> 4</u></span><span><u>(√7- √5) </u> =
</span> 5² - √7² 7² -√ 5² √7² - √5²
= <u> </u><u> 36(5 + </u><span><u>√7) </u> + <u> 88</u></span><span><u>(7-√ 5) </u> - <u> 4</u></span><span><u>(√7- √5) </u> =
</span> 25 - 7 49 - 5 7 - 5
= <u> </u><u> 36(5 + </u><span><u>√7) </u> + <u> 88</u></span><span><u>(7-√ 5) </u> - <u> 4</u></span><span><u>(√7- √5) </u> =
</span> 18 44 2
= <u> </u><u>2(5 + </u><span><u>√7) </u> + <u> 2</u></span><span><u>(7-√ 5) </u> - <u> 2 </u></span><span><u>(√7- √5) </u> =
</span> 1 1 1
= 2(5 + <span>√7) + 2</span><span>(7-√ 5) - 2 </span>(√7- √5) =
= 10 + 2√7 + 14 - 2√ 5 - 2<span>√7 + 2√5 = </span>10 + 14 = 24
5у-3х=3400 и 3у+2х=3400-1300
5у+3х=3400 и 3у+2х=2100
1) 5у=3400-3х
у=680-0,6х
2)3у+2х=2100
3(680-0,6)+2х=2100
2040-1,8+2х=2100
0,2х=2100-2040
0,2х=60
х=300- стоимость черепахи
у=680-0,6•300=500- попугая
Cosx (2cosx-7)=0
cosx=0 ili 2cosx-7=0
x=π/2+πn cosx=7/2; cosx=3,5; нет решений
Ответ. π/2+πn; n-целое
1.
5²¹ * 5 ⁻²³= 5²¹⁺⁽⁻²³⁾ = 5⁻² = 1/5² = 1/25 = 0.04
3⁻⁸ / 3⁻⁹ = 3⁻⁸⁻⁽⁻⁹⁾ = 3⁻⁸⁺⁹ = 3¹ = 3
(2²)⁻³ = 2²*⁽⁻³⁾ = 2⁻⁶ = 1/2⁶ = 1/64
2.
(a⁻³)⁵ * a¹⁸ = a⁻³*⁵ ⁺¹⁸ = a⁻¹⁵⁺¹⁸ = a³
2.4x⁻⁸y⁵ * 5x⁹y⁻⁷ = (2.4 * 5) * x⁻⁸⁺⁹ *y⁵⁺⁽⁻⁷⁾ = 12x¹ y⁻² = 12xy⁻²
3.
(1/4 * x⁻²y⁻³) ⁻² = (2⁻² x⁻²y⁻³)⁻² = 2⁴x⁴y⁶ = 16x⁴y⁶
(5x⁻¹ /3y⁻²) * 15x³y = (5* x⁻¹ * (3 * 5 ) * x³ *y¹ ) / (3y⁻²) =
= (5² * 3¹ * x⁻¹⁺³ y¹)/(3¹*y⁻²) = 5² * 3¹⁻¹ *x² * y¹⁻⁽⁻²⁾ = 25x²y³
4.
(4 ⁻⁶ * 16)/(64⁻⁵) = (4⁻⁶ * 4²) / (4³)⁻⁵ = 4⁻⁶⁺²⁻⁽⁻¹⁵⁾ = 4⁻⁴⁺¹⁵ = 4¹¹
5.
(2.5 * 10⁷) * (6.2 * 10⁻¹⁰) = (2.5*6.2) * 10⁷⁺⁽⁻¹⁰⁾ = 15.5 * 10⁻³
6.
(x ⁻¹ - y )(x - y ⁻¹)⁻¹ = (1/x - y )(x - 1/y) ⁻¹ =
= ( (1-xy)/x ) * ( (xy - 1)/y ) ⁻¹ =
= (1-xy)/x * y/(xy - 1) =
= (1 - xy)/x * ( - y/(1 -xy) ) =
= - y/x = - yx⁻¹
Думаю, достаточно...
V(t)=x`(t)=-4t³+18t²+5
v(3)=-4*27+18*9+5=-108+162+5=59