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CPT 795 views 5 replies

1).if f(x) = x+1,.g(x) = x^2+1 fog (-2) =?

ans: 6.

2).if f(x-1) = x^2-4x+8 then f(x+1) = ?

ans : x^2+4

3).the value of 2logx+2logx^2+2logx^3 -----------------------nlogx^n =

ans: n(n+1)logx.

4).the recurring decimal 2.777 -----------is expressed as

ans: 25/9.

5).one root of x^2-3x+k = 0 is 2 then k is

ans: 2.

6).the value of k for which the roots of the equation 12x^2+kx+5 = 0 in the ratio 3:2.

ans: 5.10^1/2.

Replies (5)

Finally What do you want to Express Mam !!

Could't find anything to solve !!

what is this?????????????????

isse kahte h attempt ka pressure "kya question hai...... lagta hi nahi ki question h....  :)

for 1.f(x)=x+1,g(x)=x^2+1

so, f(g(x))=f(x^2+1)

=x^2+1+1

=x^2+2

now,f(-2)=(-2)^2+2(substituting x= -2 )

=4+2=6

for2.

2logx + 2log x^2 + 2logx^3+..........+nlogx^n

=2logx + 2.2logx + 2.3logx+.......+n.nlogx(by formula logx^n=nlogx)

=2logx(1+2+3+.....+n) ( taking out 2logx as common)

=2logx.n(n+1)/2  ( 1+2+3+....+n=n(n+1)/2)

=n(n+1)logx

 

if u r facing problem in maths u can refer maths books of 11th and 12th science group of any of ur science group friends .it will surely help..


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