Note that the right triangles with sides equal to 5, 12, 13 and 9, 12, 13 both have a side equal to 12. using this fact find the area of a triangle with sides 13, 14 and 15.

Write the equation for the parabola that has x− intercepts (−2,0) and (4,0) and y− intercept (0,4).

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) = .

Askateboard ramp is in the shape of a right triangle what is the height of the ramp