Question

f[x]=3x+1/x-3 how to solve this

Answer 1

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Class 12

>>Maths

>>Relations and Functions

>>Composition of Functions

>>Let F(x) = x^3 - 3x + 1 find no. of real

Question

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Let F(x)=x

3

−3x+1

find no. of real soln, of F(F(x))=0.

Medium

Solution

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f(x)=x

3

−3x+1,f

′

(x)=3(x−1)(x+1),f

′

(x)=0

so,x=±1,howf(x)=be,atx=1,f(1)=6>0 is point of minimum

⇒f(fx)=0

⇒f(−1)=−6<0,so,x=−1 is point of maximum

⇒ff(x)=(x

3

−3x+1)−3(x

3

−3x+1)+1=0

⇒x

9

−9x

7

+3x

6

+27x

5

−18x

4

−27x

3

+27x

2

−1

It has seven real solutions.

Step-by-step explanation:

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