(a) Show that ir A is an upper triangular matrix. then AT is lower triangular. (b) Show that if A is a lower triangular matrix. then AT is upper lriangul:lr.

L20 - 5 ex. Find dy if y =n( xy). dx We can also use “Implicit Diﬀerentiation” to ﬁnd the derivative of inverse functions. For example, (sin −1x)= √ 1 . dx 1 − x2