if a+b+c=0 then a³+b³+c³ = ............

-

 As we know that

 a³+b³+c³-3abc = (a+b+c) (a²+b²+c²-ab-bc-ac) 

put value of a+b+c=0 

therefore , 

a³+b³+c³-3abc=0

a³+b³+c³=3abc

correct answer is 3abc

Comments

Post a Comment

Popular posts from this blog

Explain superposition theorem and use the principle of superposition to find the voltage Vo in the circuit

-
Image
Superposition Theorem Requirement: Power System is a complex network having number of voltage and current sources and number of loads. Now to analyze the network we need to find voltage/current at particular branch or load.  In such cases calculations for thevenin's and norton's theorem becomes difficult. We can use superposition theorem to find voltage/current at any branch or load in complex network. In this theorem only one source considered at a time and total voltage/current is sum of voltage/current obtained by considering individual source.   Statement of Superposition Theorem:
Read more

(Solved) An LVDT is connected to an amplifier of gain 250 the output terminals of which are connected to a 5 V voltmeter. The meter's scale can be read to 1/5th of a division and has 100 divisions in all. Given that a core displacement of 0.5 mm provides an output of 2 mV from the LVDT, find, 1. The sensitivity of the LVDT 2. The sensitivity of the whole system 3. The resolution of the instrument in centimeters

-
Image
 Question : An LVDT is connected to an amplifier of gain 250 the output terminals of which are connected to a 5 V voltmeter. The meter's scale can be read to 1/5th of a division and has 100 divisions in all. Given that a core displacement of 0.5 mm provides an output of 2 mV from the LVDT, find,  1. The sensitivity of the LVDT  2. The sensitivity of the whole system  3. The resolution of the instrument in centimeters Explanation : (a) Sensitivity of LVDT = Output voltage /displacement  Sensitivity of LVDT = 2mV/0.5 mm = 4 mV/mm (b)Sensitivity of whole setup = amplification factor*sensitivity of LVDT  Sensitivity of whole setup = 250*(4 mV/mm) = 1000 mV/mm (c) The resolution of the instrument in centimeters = minimum voltage that can be read by instrument /sensitivity of whole setup  There are 100 divisions to measure upto 5V.  So 1 division can read 5/100 = 0.05V Scale can read 1/5 of a division.  So minimum voltage that can be read = 0.05/5 ...
Read more

(Solved) J. B. Gupta important questions from model test paper with solution

-
Important questions of JB Gupta book Model Test Paper 2 : (We are working to provide detailed solutions of each question. We are updating this page.) Question 1 : In a magentic material, hysteresis loss takes place primarily due to  (a) rapid reversals of its magnetisation  (b) flux density lagging behind magnetis ing force  (c) molecular friction  (d) its high retentivity Show Answer Ans: D   Question 2 : On which of the following factors does the resolution of a potentiometer depend? (a) Size of wire  (b) Type of contact (c) Composition of wire material  (d) Shape of wire cross-section Show Answer Ans: A   Question 3 : The braking retardation is usually in the range (a) 0.15 to 0.30 km phps  (b) 0.30 to 0.6 km phphs  (c) 0.6 to 2.4 km phps  (d) 3 to 5 km phps  (e) 10 to 15 km phphs Show Answer Ans: D Question 4 : Which of the following methods is used for reduction/elimination of harmonic torques? (a...
Read more