# KERALA Class 11 Science Mathematics Free Doubts and Solutions

### Kerala - XI Science - Mathematics

## Find 3nP4=5(n-1)P4 , for n>4 ? (From 7th chapter permutations and combinations.)

**antonyjojy999**15th January 2016, 7:11 PM

### Kerala - XI Science - Mathematics - Sequences and Series

## If the sum of a certain no. of terms of the A.P. 25,22,19,...is 116.Find the last term.

**mythili Suresh**2nd September 2015, 8:14 PM

### Kerala - XI Science - Mathematics - Principle of Mathematical Induction

## P(n): 1+3+3^2+.....+3^n-1=(3^n-1)/2.
If P(k) is true prove P(k+1) is true.

**Deebu**1st February 2015, 4:08 PM

### Kerala - XI Science - Mathematics - Relations and Functions

## Draw the graph of the function f(x)=x+1,where x is an element of R.
[please explain why the graph is a V shape and not a slanding line. Isn't V shape the graph for modulus function?]

**Deebu**1st February 2015, 1:19 PM

### Kerala - XI Science - Mathematics - Limits and Derivatives

## Find the derivative of f(x)=Sin x using the first priciple.
[I got everything till the last step. How can cos(x+(h/2)).(sin h/2)/(h/2)=cosx.1?]
[also in short what exatly is the first principle?]

**Deebu**1st February 2015, 1:31 AM

### Kerala - XI Science - Mathematics - Permutations and Combinations

## What is the mnimum number of ways of choosing 4 cards from a pack of 52 playing cards? in how many of these:
1) are 4 card of the same suit?
2)do 4 cards belong to 4 different suits?
[I found the answer to 1) as 13C4+13C4+ 13C4+ 13C4. but when I don't understand how to solve question number 2. According to solutions it is given as 13C1 x 13C1 x 13C1 x 13C1= 13^4.
I understand how we got 13C1 but I don't understand why multiplication was used and not division]

**Deebu**31st January 2015, 6:55 PM

### Kerala - XI Science - Mathematics - Limits and Derivatives

## Find the distence between 4x-3y-9=0 and 8x-6y-21=0

**Deebu**28th December 2014, 12:29 AM

### Kerala - XI Science - Mathematics - Limits and Derivatives

## Find the term indipendent of x in (((3/2)x^2) - (1/3x))^6

**Deebu**28th December 2014, 12:27 AM

### Kerala - XI Science - Mathematics - Limits and Derivatives

## Find the locus of the set of points P such that distence from A(2,3,4) is equal to twice the distence from B(-2,1,2).
[ I took P as (x,y,z) and found distence from A and distence from B. Now what?]

**Deebu**28th December 2014, 12:23 AM

### Kerala - XI Science - Mathematics - Limits and Derivatives

## Find the point which trisect (4,0,1),(2,4,0).

**Deebu**28th December 2014, 12:20 AM

## Browse free questions and answers Chapters

- 1 Sets
- 2 Relations and Functions
- 3 Principle of Mathematical Induction
- 4 Binomial Theorem
- 5 Sequences and Series
- 6 Straight Lines
- 7 Conic Sections
- 8 Introduction to Three Dimensional Geometry
- 9 Limits and Derivatives
- 10 Mathematical Reasoning
- 11 Statistics
- 12 Probability
- 13 Trigonometric Functions
- 14 Complex Numbers and Quadratic Equations
- 15 Permutations and Combinations
- 16 Linear Inequalities