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Last updated at Sept. 11, 2020 by Teachoo
Transcript
If a = 5 + 2โ6 and b = 1/๐, then what will be the value of ๐^2+๐^2 ? a = 5 + 2โ6 b = 1/๐ = 1/(5 + 2โ6) = 1/(5 + 2โ6) ร (5 โ 2โ6)/(5 โ 2โ6) = (5 โ 2โ6)/(5^2 โ (2โ6)^2 ) = (5 โ 2โ6)/(25 โ 24) We know that ใ(๐+๐)ใ^2 = ๐^2+๐^2+ 2๐๐ ๐^๐+๐^๐ = ใ(๐+๐)ใ^๐ โ ๐๐๐ Here, ๐+๐ = (5+2โ6)+5(5โ2โ6) ๐๐ = (5+2โ6) (5โ2โ6) Thus, ๐^2+๐^2 = ใ(๐+๐)ใ^2 โ 2๐๐ ๐^2+๐^2=ใ10ใ^2โ2 ร 1 =100โ2 =๐๐
Rationalising
Add (3โ2+7โ3) and (โ2โ5โ3)
Divide 5โ11 by 3โ33
Multiply 2โ15 by 7โ5
Simplify (โ5+โ7)^2
Simplify (โ4โโ13)(โ4+โ13)
Simplify (9โโ3)(9+โ3)
Simplify (3โ5โ5โ2)(4โ5+3โ2)
Rationalise the denominator of 8/โ7
Rationalise the denominator of 1/((8 + 5โ2))
Simplify (7โ3)/(โ10 + โ3)โ(2โ5)/(โ6 + โ5)โ(3โ2)/(โ15 + 3โ2)
Multiple Choice Questions - Chapter 1 Class 9 Maths
Example 17
If a and b are rational numbers and (โ11 โ โ7)/(โ11 + โ7) = a โ bโ77, find the value of a and b
Example 18
Find the values of a and b if (7 + 3โ5)/(3 + โ5) โ (7 โ 3โ5)/(3 โ โ5) = a+โ5 b
If x = 1/(2 โ โ3), find the value of x^3 โ 2x^2 โ 7x + 5
Ex 1.5, 5 (i)
If a = 5 + 2โ6 and b = 1/a, then what will be the value of a^2+b^2 ? You are here
Example 19
Example 20 Important
Rationalising
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