let f(x)=ax^3 + bx^2 + cx + dsinx.Find d condition dat f(x) is always one-one function.

3 years ago


Answers : (1)


Dear MAnuj,

 f(x)= ax3+ bx2+ cx+dsinx

d f (x)/dx=3ax^2 + 2bx + c + dcosx <0 (say)

i.e. 3ax^2 + 2bx + c + d<0   (as max. of cosx =1)

and b^2 -4ac<0 (for im roots)

u get : b^2 < 3a(c+d)

but if u hd taken 3ax^2 + 2bx + c + dcosx >0

then take 3ax^2 + 2bx + c - d>0 

Best Of Luck...!!!!

Cracking IIT just got more exciting,It’s not just all about getting assistance from IITians, alongside Target Achievement and Rewards play an important role. ASKIITIANS has it all for you, wherein you get assistance only from IITians for your preparation and win by answering queries in the discussion forums. Reward points 5 + 15 for all those who upload their pic and download the ASKIITIANS Toolbar, just a simple  to download the toolbar….

So start the brain storming…. become a leader with Elite Expert League ASKIITIANS


Aman Bansal

Askiitian Expert


3 years ago

Post Your Answer

More Questions On Differential Calculus

Ask Experts

Have any Question? Ask Experts
Post Question
Answer ‘n’ Earn
Attractive Gift
To Win!!!
Click Here for details
TANGENTS AND NORMALS find the points on the curve y = x^3 – 2x^2 – 2x at which the tangent lines are parallel to the line y=2x -3
Ans: Hello Student, Please find answer to your question below Slope of line = 2 Put in the curve and get y.
Jitender Singh 4 months ago
x=a cos( theta) + b sin(theta) y=a sin(theta) – b cos( theta) prove that y*y2-x*y1+y=0
Ans: Hello Student, Please find answer to your question below Differentiate Differentiate
Jitender Singh 6 months ago
If co domain is not given and we have to tell it is into or onto . How will we tell?
Ans: If co domain is not specified, we take it as a set of real numbers . Now you can check, whether range is set of real numbers or a subset of real number. If it is a set of real number,...
Jitender Singh 6 months ago
Vertex of the parabola with focus (a,b) and directrix x/a + y/b = 1
The vertex would lie between the focus and the foot of the perpendicular from the focus to the directrix. Find the foot of perpendicular from the focus to the directri. The vertex will be...
Ravi 2 months ago
This question is actually based on 3 Dimension. A line makes angle alpha, beta, gamma and delta with four diagonals of a cube then cos 2 alpha + cos 2 beta + cos 2 gamma +cos 2 delta is...
The answer to your question is 4/3. It has a detailed but simple proof. For that, plz refer to R.D.Sharma Class 12 part-II in the chapter Direction Cosines and Direction Ratios.
Yash Jain 25 days ago
One of the two events must occur. if the chance of one is 2/3 of the other, then the odds in the favor of the other are:
Hello Student, The upper is favor and lower is not in favor so 3 is not in favor means its in favor of other =>3/2 Thanks & Regards Arun Kumar Btech, IIT Delhi Askiitians Faculty
Arun Kumar 7 months ago
View all Questions »