C-05-Q117mediumsingle_mcq

Which of the following is an identity?

a $(x + 1)^2 + (x - 1)^2 = 4x$
b $(x + 1)^2 + (x - 1)^2 = 2(x^2 + 1)$
c $(a + b)^2 + (a - b)^2 = 2ab$
d $(a - b)^2 = a^2 + 2ab + b^2$

ব্যাখ্যা

Expanding gives $(x+1)^2+(x-1)^2 = (x^2+2x+1)+(x^2-2x+1)=2x^2+2=2(x^2+1)$ , which holds for every value of $x$ . An equation true for all values of the variable is an identity, whereas the other options are false.

এই অধ্যায়ের আরও প্রশ্ন

C-05-Q118The two roots of are—
C-05-Q119Coefficient of in is—
C-05-Q120Solution set of is—
C-05-Q121Solve :
C-05-Q122From the values of are—
C-05-Q123Solve :
C-05-Q124Solve :
C-05-Q125Solution set of requires solving—
C-05-Q126has solution set—
C-05-Q127Solution set of comes from—

Equations in One Variable — সব প্রশ্ন দেখুন (170টি) →

Which of the following is an identity?

(x + 1)^2 + (x - 1)^2 = 4x

(x + 1)^2 + (x - 1)^2 = 2(x^2 + 1)

(a + b)^2 + (a - b)^2 = 2ab

(a - b)^2 = a^2 + 2ab + b^2