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Home » Let f : R → R : f(x) = x + 1 and g : R → R : g(x) = 2x – 3.Find (i)(f + g) (x) (ii) (f – g) (x) (iii) (fg) (x) (iv)(f/g) (x)
Let f : R → R : f(x) = x + 1 and g : R → R : g(x) = 2x – 3.Find
(i)(f + g) (x)
(ii) (f – g) (x)
(iii) (fg) (x)
(iv)(f/g) (x)
CBSE | Class 11 | Excercise 3E | Functions | Maths | RS Aggarwal
Let f : R → R : f(x) = x + 1 and g : R → R : g(x) = 2x – 3.Find
(i)(f + g) (x)
(ii) (f – g) (x)
(iii) (fg) (x)
(iv)(f/g) (x)

Answer : (i) Given:

f(x) = x + 1 and g(x) = 2x -3

  • To find: (f + g) (x) (f + g) (x) = f(x) + g(x)

= (x + 1) + (2x -3)

= x + 1 + 2x – 3

= 3x – 2

Therefore,

(f + g) (x) = 3x -2

  • To find: (f – g) (x) (f – g) (x) = f(x) – g(x)

= (x + 1) – (2x -3)

= x + 1 – 2x + 3

= 4 – x

Therefore,

(f – g) (x) = 4 – x

  • To find: (fg)(x) (fg)(x) = f(x). g(x)

= (x+1) (2x-3)

= x(2x) -3(x) +1(2x) -1(3)

= 2×2 – 3x + 2x -3

= 2×2 – x -3

Therefore,

(fg)(x) = 2×2 – x -3

(iv) To find

Sol 

  • Therefore,

 

i

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