what is the average(mean) value of 2t-3t+4 over interval -1≤t≤1?

what is the average(mean) value of 2t-3t+4 over interval -1≤t≤1?
what is the average(mean) value of 2t-3t+4 over interval -1≤t≤1?

what is the average(mean) value of 2t-3t+4 over interval -1≤t≤1?
这句话的意思是说 函数2t-3t+4在-1≤t≤1的范围内,平均值是多少 首先设f（t)=2t-3t+4,对f(t)求导,确定是否能在-1≤t≤1范围内取到最大值或者是最小值 f'(t)=6t(t-1),令f'(t)=0,所以t=1或0,又因为当-1≤t≤0时,f（t）递增,0≤t≤1,f（t）递减,这由图像可看出来 所以f(0)是最大值,为4,f(1)>f(-1),所以f(-1)是最小值-1 平均值就是（4+-1)/3=1