86405 ∫−ππsinx[f(cosx)]dx=
(D) : Given,∫−ππsinx[f(cosx)]dx∵∫−aag(x)dx=0, for odd function.g(x)=sinx[f(cosx)]g(−x)=sin(−x)[f(cos(−x))]=−sinx[f(cosx)]=−g(x)Hence, it is odd functionThen, ∫−ππg(x)dx=0So, ∫−ππsinx[f(cos)]=0Hence, option (d) is correct.
86415 ∫0πxsinx(3cos2x+2sinx+sin3x−3)dx=
(A) : Let,I=∫0πxsinx(3cos2x+2sinx+sin3x−3)⋅dx=∫0πxsinx(3−3sin2x+2sinx+sin3x−3)⋅dxI=∫0πx(sin2x−3sinx+2)⋅dxI=∫0π(π−x)(sin2(π−x)−3sin(π−x)+2)⋅dxI=∫0π(π−x)(sin2x−3sinx+2)⋅dxAdding equations (i) and (ii)2I=π∫0π(sin2x−3sinx+2)dxI=π2[∫0π(1−cos2x)2⋅dx+[3cosx+2x]0π]=π2[12x−sin2x4]0π+(−3−3)+(2π)=π2[π2−6+2π]=π4[π−12+4π]=π4(5π−12)
86416 ∫−11|x|xdx=
(C) : Given,∫−11|x|xdxf(x)=|x|x{−xx,x<0⇒−1,x<0xx,x>0⇒1,x>0}∴I=∫−10(−1)dx+∫011dx=[−x]−10+[x]01=−1+1=0
86417 ∫25x+2x−1+x−2x−1dx=
(C) : : Let, I=∫25[x+2x−1+x−2x−1]dx=∫5[x−1+1+2x−1+x−1+1−2x−1⋅dx=∫25[(x−1+1)2+(x−1−1)2]⋅dx=2∫25x−1⋅dx=2∫25(x−1)1/2⋅dx=2×23[(x−1)3/2]25=43[43/2−13/2]=43[8−1]=4×73=283