Question

Find the EXACT value of sin(2A) if cscA=5/4
Assume A is a Quadrant I angle in standard position.
sin(2A)=

Answer 1

Think about what the relationship between sine and cosecant is. 1 over 5/4 is like 1 times 4/5 or just 4/5. Then, what is 2 times 4/5?

Answer 2

cscA = 5/4.
sinA = 4/5,
A = 53.13o.
2A = 106.26o
sin2A = sin106.26 = 0.96 = 96/100 = 24/25.