The t-formulae are formulae for the trigonometric functions using the substitution to obtain the following formulae:
Solving Equations
To solve questions, you need to find if not directly given, then use the t-formula for what you’re trying to find. You generally find
Finding or it will either be given in the question or the reciprocal function Then using the identity to obtain the other function Either sine or cosine then choose the correct sign for the square root based on boundary conditions for in the problem. Then use
Weierstrass Substitution For Integrals
You can use the t-formulae as a substitution for integrals it should be self explanatory from there but a key fact to remember is