Trigonometric Identities

sinx

-sinx

cosx

2sinx

1/cosθ

1/sinθ

cosθ/sinθ

sinθ/cosθ

1/cosθ

1/sinθ

1/tanθ

1/secθ

sin²θ/cos²θ

1

0

cos²θ/sin²θ

secθ

cos²θ

sin²θ

sin²θ/cos²θ

sin²θ

cosθ

tanθ

1- sin²θ

2secθ

cot²θ

tan²θ

sec²θ + 1

tanx

cotx

sin²x

cos²x

Step 1: Combine cosx + cosx which is  $$\cos^2x$$  

Step 1: Combine  cosx + cosx which is  $$2\cos x$$  

Step 2: Rewrite  $$\frac{\cos x}{\sin x}$$  as tanx

Step 2: Rewrite  $$\frac{\cos x}{\sin x}\$$  as cotx

Step 1: Cross Multiply cosx and sinx and simplify

Step 1: Cross Add cosx and sinx and simplify

Step 2: Rewrite  $$\sin^2x+\cos^2x$$ using pythgorean identity in the denominator to 1

Step 2: Rewrite  $$\sin^2x+\cos^2x$$  using Pythagorean identity in the numerator to 1

Step 3: Rewrite  $$\frac{1}{\sin x\cos x}as\ \sec x\csc x$$  using reciprocal identity