数学题目：微积分，函数的导数，极限求大神帮帮忙了

11、lim n→∞ [ 1 + 1/n + 1/n^2 ) = 1 + 0 - 0 = 1；12、积分上限是 3，下限是 1，被积函数是lnx ；13、∫( 1，4 ) dx = [x]( 1，4 ) = [ 4 - 1 ] = 3；∫( -1，2 ) x^2dx = [x^3/3]( -1，2 ) = [ 2^3/3 - (-1)^3/3 ] = 3；14、cosα = -√[ 1 - (3/5)^2 ] = -4/5；tanα = (3/5)/(-4/5) = -3/4；15、⑴、limx→2 ( x^2 - 4 )/( x - 2 )= lim x→2 ( x + 2 )( x - 2 )/( x - 2 )= lim x→2 ( x + 2 )= 2 + 2= 4；⑵、lim x→0 ( 2sinx/x ) + 1= 2[ lim x→0 ( sinx/x ) ] + 1= 2 * 1 + 1= 3；16、⑴、y = e^x + x^2，y' = e^x + 2x；⑵、y = lnx - sinx，y' = 1/x - cosx ；