Trigonometry

Sum and Difference Identities Calculator

Calculate sin(A±B), cos(A±B), and tan(A±B) using sum and difference formulas.

Sum (A + B)

sin(A+B):0.966
cos(A+B):0.259
tan(A+B):3.732

Difference (A - B)

sin(A-B):0.259
cos(A-B):0.966
tan(A-B):0.268

How to Use This Calculator

1

Enter Values

Fill in the required fields with your numbers.

2

Calculate

Click calculate or see results update in real time.

3

Read Results

View detailed breakdowns and explanations below.

📘 Sum Formulas

sin(A + B) = sin(A)cos(B) + cos(A)sin(B)
cos(A + B) = cos(A)cos(B) - sin(A)sin(B)
tan(A + B) = [tan(A) + tan(B)] / [1 - tan(A)tan(B)]

🎓 Difference Formulas

sin(A - B) = sin(A)cos(B) - cos(A)sin(B)
cos(A - B) = cos(A)cos(B) + sin(A)sin(B)
tan(A - B) = [tan(A) - tan(B)] / [1 + tan(A)tan(B)]

💡 Memory Tip

Notice the patterns:

  • Sine: Same operation (+ for sum, - for difference)
  • Cosine: Opposite operation (- for sum, + for difference)
  • Tangent: Fraction form with opposite in denominator

🚀 Applications

  • Simplification: Expanding or factoring trig expressions
  • Solving Equations: Breaking complex angles into simpler parts
  • Physics: Wave interference and superposition
  • Engineering: Signal processing and modulation

⚡ Special Cases

These formulas lead to other important identities:

  • Double Angle: Let A = B
  • Cofunction: Let B = 90°
  • Product-to-Sum: Add and subtract the formulas

Frequently Asked Questions

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