can u plz integrate these 1)sec5xtanx ans 1/5(sec5x) 2)(cos2x)/(sinx +cosx)2 = ans log lsinx+cosxl 3)(xe-1 + ex-1 )/(xe + ex ) ans 1/e{logIxe +exl} can u also tell me how(on wat basis) we should take substitutions like t,z etc 4)(sin2x)/(sin5xsin3x) ans 1/3LogIsin3xI-1/5logIsinxI 5)(1-tanx)/(1+tanx) ans log Icosx+sinxI 6)cot3x ans -1/2cot2x - log lsinxl 7)(sin2x)/(sin5xsin3x) ans 1/3loglsin3xl - 1/5 loglsin5xl 8)1/(a2sin2x + b2cos2x) ans 1/ab(tan-1(atanx/b) 9)1/(ex + e-x )2 ans -1/(2(1+e2x )) 10) 1/(ex +1)(1+e-x ) ans -1/(1+ex ) 11)(x+2)/ (1-x2 ) ans - (1-x2 ) + 2sin-x 12)cosec4x ans -cotx -(cot3x)/3 13) tan3x ans -loglsecxl +(tan2 x)/2