Introduction to Trigonometric Functions Return to home page

Trig functions are the relationships amongst various sides in right triangles. You know by the Pythagorean theorem that the sum of the squares of each of the smaller sides equals the square of the hypotenuse,

You know in the above triangle that c b C B a You know in the above triangle that Trig functions are how the relationships amongst the lengths of the sides of a right triangle vary as the other angles are changed.

How does this relate to trig? sin(θ) = b/c cos(θ) = a/c tan(θ)= b/a c b θ C B a

Remember SOHCAHTOA Sine: Opposite/ Hypotenuse Cosine: Adjacent/ Hypotenuse Tangent: Opposite/ Adjacent

Practice!? c=? sin(θ)= cos(θ)= tan(θ)= A c 3 θ C B 4

Practice!? b=? sin(θ)= cos(θ)= tan(θ)= θ 15 9 b

New Trig! sin(θ)= cos(θ)= tan(θ)= csc(θ)= sec(θ)= cot(θ)=

More Practice! sin(θ)= cos(θ)= tan(θ)= csc(θ)= sec(θ)= cot(θ)= θ 15 9 12 csc(θ)= sec(θ)= cot(θ)=

More Practice! sin(θ)= cos(θ)= tan(θ)= csc(θ)= sec(θ)= cot(θ)= 15 9 θ 12 csc(θ)= sec(θ)= cot(θ)=

Time for a worksheet!