Tính : 15^30/45^15
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\(\frac{15^{30}}{45^{15}}=\frac{\left(3.5\right)^{30}}{\left(9.5\right)^{15}}=\frac{3^{30}.5^{30}}{9^{15}.5^{15}}=\frac{3^{30}.5^{30}}{3^{30}.5^{15}}=5^{15}\)
Chỉ làm đến thế thôi
12 + 12 = 24
10 + 30 = 40
61 - 50 = 11
15 + 15 = 30
98 - 15 = 83
12 + 45 = 57
36 + 45 = 80
tk mình nha
24
40
11
30
83
57
81
chúc bạn học tốt HOSHIMIYA ICHIGO chào nhé
Ta có:
\(\cos {15^0} = \cos \left( {{{45}^0} - {{30}^0}} \right) = \cos {45^0}\cos {30^0} + \sin {45^0}\sin {30^0} = \frac{{\sqrt 2 }}{2}.\frac{{\sqrt 3 }}{2} + \frac{{\sqrt 2 }}{2}.\frac{1}{2} = \frac{{\sqrt 6 + \sqrt 2 }}{4}\)
\(\sin {15^0} = \sin \left( {{{45}^0} - {{30}^0}} \right) = \sin {45^0}\cos {30^0} - \cos {45^0}\sin {30^0} = \frac{{\sqrt 2 }}{2}.\frac{{\sqrt 3 }}{2} - \frac{{\sqrt 2 }}{2}.\frac{1}{2} = \frac{{\sqrt 6 - \sqrt 2 }}{4}\)
\(\tan {15^0} = \tan \left( {{{45}^0} - {{30}^0}} \right) = \frac{{\tan {{45}^0} - \tan {{30}^0}}}{{1 + \tan {{45}^0}\tan {{30}^0}}} = \frac{{1 - \frac{{\sqrt 3 }}{3}}}{{1 + \frac{{\sqrt 3 }}{3}}} = 2 - \sqrt 3 \)
\(\cot {15^0} = \frac{1}{{\tan {{15}^0}}} = \frac{1}{{2 - \sqrt 3 }}\)
Bài 2:
\(a,45+170+25+30\)
\(=\left(45+25\right)+\left(170+30\right)\)
\(=60+200=260\)
Bài 3:
\(a,\left(x-6\right).5=150\)
\(x-6=150:5\)
\(x-6=30\)
\(x=30+6\)
\(x=36\)
\(b,2^5.\left(3x-2\right)=2^3.2^6\)
\(2^5.\left(3x-2\right)=2^{3+6}\)
\(2^5.\left(3x-2\right)=2^9\)
\(3x-2=2^9:2^5\)
\(3x-2=2^4=16\)
\(3x=16+2\)
\(3x=22\)
\(x=22:3\)
\(x\approx7,3\)
\(c,100-7.\left(x-5\right)=51\)
\(7.\left(x-5\right)=100-51\)
\(7.\left(x-5\right)=49\)
\(x-5=49:7\)
\(x-5=7\)
\(x=7+5\)
\(x=12\)
Phần d) bạn thiếu dữ liệu ạ.
a]27/45+25/15=3/5+5/3=34/15
b]28/32+45/72=7/8+5/8=12/8=3/2
c]8/28+5/30=2/7+1/6=19/42
`= 12 xx 45 + 12 xx 15 + 12 xx 30`
`= 12 xx (45+15+30)`
`= 12 xx 90`
`= 1080`.
a, 21.35-3.25.7=21.35-21.25=21.(35-25)=21.10=210
b, 77-11.(30+7)=77-330-77=-330
c, 85.(35-27)-35.(85-27)=85.35-85.27-35.85+35.27=0
d, 47.(45-15)-47.(45+15)=47.45-47.15-47.45-47.15=-2(47.15)=1410
a, 21.35-3.25.7=21.35-21.25=21.10=210
b,77-11.(30+7)=77-11.30-11.7=-11.30=-330
c,85.(35-27)-35.(85-27)=85.35-85.27-85.35+35.27=27.(-50)=-1350
d, 47.(45-15)-47.(45+15)=47.45-47.15-47.45-47.15=-47.30=-1410
\(\frac{15^{30}}{45^{15}}=\frac{\left(3.5\right)^{30}}{\left(9.5\right)^{15}}=\frac{3^{30}.5^{30}}{9^{15}.5^{15}}=\frac{3^{30}.5^{30}}{3^{2.15}.5^{15}}=\frac{3^{30}.5^{30}}{3^{30}.5^{15}}=5^{15}\)
@@ đấy là tính máy tính
\(\frac{15^{30}}{45^{15}}=\frac{\left(15^2\right)^{15}}{45^{15}}=\frac{225^{15}}{45^{15}}=5^{15}\)