Which expression is equal to (6•5)^4

Suppose i flip two identical coins. what is the probability that i get one head and one tail?

Si la base de un triángulo isósceles mide 70 m y el ángulo opuesto a ésta mide 58°; entonces ¿cuánto mide la altura de dicho triángulo? a) 21.87 m. b) 40.01 m. c) 43.74 m. d) 63.14 m.

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.