Question

A student solved the equation sin2x/cosx=2, 0(greater than or equal)x(greater than or equal)pi, and found an answer of pi/2. Describe the student's error.

Please show all steps.

Answer 1

The student forgot about the double angle identity.

Explanation:

sin2x/cosx=2

This is the double angle identity

sin2x=2sin(x)cos(x)

(2sinxcosx)/cosx=2

2sinx=2

sinx=1

x=sin^-1(1)

x=90 degrees OR pi/4

This was my answer for the test and got full points :)