Advertisements
Advertisements
प्रश्न
Using identity, find the value of (1.9) × (2.1)
Advertisements
उत्तर
(1.9) × (2.1) = (2 – 0.1) × (2 + 0.1)
Substituting a = 2 and b = 0.1 in
(a – b)(a + b) = a2 – b2 we have
(2 – 0.1)(2 + 0.1) = 22 – (0.1)2
(1.9) × (2.1) = 4 – 0.01
(9.9)(2.1) = 3.99
APPEARS IN
संबंधित प्रश्न
(5 + 20)(–20 – 5) = ?
a2 – b2 = (a + b) ______.
Factorise the following using the identity a2 – b2 = (a + b)(a – b).
1331x3y – 11y3x
Factorise the following using the identity a2 – b2 = (a + b)(a – b).
x4 – y4
Factorise the following using the identity a2 – b2 = (a + b)(a – b).
(a – b)2 – (b – c)2
The sum of first n natural numbers is given by the expression `n^2/2 + n/2`. Factorise this expression.
The sum of (x + 5) observations is x4 – 625. Find the mean of the observations.
Verify the following:
(ab + bc)(ab – bc) + (bc + ca)(bc – ca) + (ca + ab)(ca – ab) = 0
Verify the following:
(a2 – b2)(a2 + b2) + (b2 – c2)(b2 + c2) + (c2 – a2) + (c2 + a2) = 0
Find the value of `(6.25 xx 6.25 - 1.75 xx 1.75)/(4.5)`
