#1**+1 **

If tan theta is equal to 3. Calculate cos theta.

Draw a right angled triangle

mark an acute angle as theta.

opposite is 3

adjacent is 1

work out the hypotenuse using pythagoras's theorum

read cos(theta) off the triangle.

BUT tan is positive in the 1st or third quadrant so cos(theta) can be pos or neg.

Melody
Jun 17, 2017