Question
_5^9 3 x^2 3 x^2+ (588-84 x+3 x^2 ) d x is equal to
_5^9 3 x^2 3 x^2+ (588-84 x+3 x^2 ) d x is equal to
A. 2
Let I= _5^9 3 x^2 d x 3 x^2+ (588-84 x+3 x^2 ) ...(i) aligned & = _5^9 3 x^2 d x 3 x^2+ 3(14-x)^2 \\ & = _5^9 3(14-x)^2 d x 3(14-x)^2+ 3(14-(14-x))^2 \\ & [ _a^b f(x) d x= _a^b f(a+b-x) d x ] aligned I= _5^9 3(14-x)^2 d x 3(14-x)^2+ 3 x^2 ...(ii) Adding Eqs. (i) and (ii), we get aligned & 2 I= _5^9 3 x^2+ 3(14-x)^2 3(14-x)^2+ 3 x^2 d x \\ & 2 I = _5^9 d x=9-5=4 I=2 aligned
Related: Mathematics — Definite Integration · All PYQ Banks