Is g = {(1, 1), (2, 3), (3, 5), (4, 7)} a function? If g is described by g (x) = α x + β, then what value should be assigned to α and β.
In order to determine if g = {(1, 1), (2, 3), (3, 5), (4, 7)} represents a function or not, we need to validate if g satisfies the condition of a relation to be a function.
A relation f from a set A to a set B is said to be a function if every
element of set A has one and only one image in set B.
By definition of function we can say that no two distinct ordered pairs in a function have the same first element.
We have,
g = {(1, 1), (2, 3), (3, 5), (4, 7)}
we observe that each first element of ordered pairs is related to only one element.
Hence, g is a function.
Given,
g(x) = α x + β and g(1) = 1
⇒ α + β = 1 ……(i)
g(2) = 3, we get
⇒ α 2 + β = 3 ……(ii)
g(3) = 5, we get
⇒ α 3 + β = 5 ……(iii)
g(4) = 7, we get
⇒ α 4 + β = 7 ……(iv)
Solve any 2 equations from (i),(ii),(iii) and (iv) to find two unknowns α and β
On solving (i) and (ii), we get
α = 2 and β = -1
Hence, the function g(x) = 2x – 1