RS Aggarwal - Mathematics

Book: RS Aggarwal - Mathematics

Chapter: 3. Functions

Subject: Maths - Class 11th

Q. No. 3 of Exercise 3E

Listen NCERT Audio Books to boost your productivity and retention power by 2X.

3

. Let f: R R: f(x) = x3 + 1 and g: R R: g(x) = (x + 1). Find:

(i) (f + g) (x)


(ii) (f – g) (x)


(iii) (1/f) (x)


(iv) (f/g) (x)


(i) Given:


f(x) = x3 + 1 and g(x) = x + 1


(i) To find: (f + g) (x)


(f + g) (x) = f(x) + g(x)


= (x3 + 1) + (x + 1)


= x3 + 1 + x + 1


= x3 + x + 2


Therefore,


(f + g) (x) = x3 + x + 2


(ii) To find: (f - g) (x)


(f - g) (x) = f(x) - g(x)


= (x3 + 1) – (x + 1)


= x3 + 1 – x - 1


= x3 - x


Therefore,


(f - g) (x) = x3 - x


(iii) To find




Therefore,



(iv) To find





(Because a3 + b3 = (a + b) (a2 – ab + b2))


Therefore,


= x2 – x + 1


Chapter Exercises

More Exercise Questions