The sum of the first 10 terms of an arithmetic sequence is 235 and the
sum of the second 10 terms is 735. find the first term and the common
difference.

Prove (a) cosh2(x) − sinh2(x) = 1 and (b) 1 − tanh 2(x) = sech 2(x). solution (a) cosh2(x) − sinh2(x) = ex + e−x 2 2 − 2 = e2x + 2 + e−2x 4 − = 4 = . (b) we start with the identity proved in part (a): cosh2(x) − sinh2(x) = 1. if we divide both sides by cosh2(x), we get 1 − sinh2(x) cosh2(x) = 1 or 1 − tanh 2(x) = .

Find the missing variable for a parallelogram: a = latex: 32in^2 32 i n 2 h = b = 6.3 in (1in=2.54cm)

Ab and bc are tangent to circle d. find x is ab = 3x + 8 and bc = 26. find x