Unit-1: Arithematic
(a) Number system
(b) Exponents of real numbers, surds and rationalisation
Q1.
(3 +)(3 -)is a rational number.
(a) yes (b)no (c) can't say.
Solution.
(a + b) (a - b) = a
2 - b
2
So, (3 +
)(3 -
) = 9 - 3 = 6
Thus 6 is a rational number.
Solution
Q2.
Sum of two irrational number ia always an irrational number.
(a) True (b)False (c) Can't say.
Solution.
False, Sum of two irrational number can be rational or irrational number
(3 +
)+(3 -
)
= 6(Rational number)
(3 +
)+(3 +
) = 6 + 2
(Irrational number)
Solution
Q3.
9 + is a _____ number ..
Solution.
9 +
is a irrational number.
9 is a rational number and
is an irrational number and as we known that sum of rational number and an irrational number is always
an irrational number.
Solution
Q4.
Insert a rational number and an irrational number between 3 and 4.
Solution.
If a and b are rational numbers and ab is not a perfect square, then
is an irrational numbers between a and b
Rational number between
a and b is (a + b)/2
So, irrational number:
rational number : (3 + 4) /2 = 3.5 .
Solution
Q5.
Can we represent an irrational number on number line.
Solution.
Yes.
Solution
Q6.
Evaluate (64)-2/3 .
Solution.
= (43)-2/3 = 4-2 = 1/(42) = 1/16
Solution
Q7.
Find the value of x, if 5(x - 4). 3(2x - 10) = 225 .
Solution.
5(x - 4). 3(2x - 10) = 52 x 32
x - 4 = 2 and 2x - 10 = 2
x = 6 , 2x = 12
x = 6
Solution
Q8.
Simplify .
Solution.
Solution
Q9.
Find x, If 24 x 42 =4x .
Solution.
24 x 24 = 22x
28 = 22x
8 = 2x
x = 4.
Solution
Q10.
If (x- 1)3 = 64, find the value of x3.
Solution.
(x - 1)3 = 43
x - 1 = 4
x = 5
So, 53 = 125
Solution