# Trig identities

Printable View

• October 28th 2009, 02:12 PM
l flipboi l
Trig identities
Hello

can someone please verify this answer for me?

(1+cotA) / (cscA)

(1+cosA/sinA) / 1 * (sinA/1)/1

answer is CosA
• October 28th 2009, 02:16 PM
e^(i*pi)
Quote:

Originally Posted by l flipboi l
Hello

can someone please verify this answer for me?

(1+cotA) / (cscA)

(1+cosA/sinA) / 1 * (sinA/1)/1

answer is CosA

I don't follow what you did with the denominator? If you recall the way of dividing fractions we treat it as multiplying

$\left(1+\frac{cosA}{sinA}\right) \times sinA$

$\left(\frac{sinA+cosA}{sinA}\right) \times sinA = sinA + cosA$

edit: the answer cannot be $cosA$ because the identity doesn't hold for $A = \frac{\pi}{2}$