How do you multiply and simplify (sinx-cosx)^2?

1 Answer
Nov 18, 2016

Use the pattern (a - b)^2 = a^2 - 2ab + b^2 and then simplify:

(sin(x) - cos(x))^2 = 1 - sin(2x)

Explanation:

Using the pattern:

(sin(x) - cos(x))^2 = sin^2(x) - 2sin(x)cos(x) + cos^2(x)

Use the identity sin^2(x) + cos^2(x) = 1

(sin(x) - cos(x))^2 = 1 - 2sin(x)cos(x)

Use the identity sin(2x) = 2sin(x)cos(x)

(sin(x) - cos(x))^2 = 1 - sin(2x)