how to find the values of cos 135 or cos 145 or sin 105 or tan 145 etc.. means the angle which r greater than 90 degree?
cos(135) = cos (90 + 45)
Here you have to check whether cos is positive in the second quadrant or not, and when you use 90 degrees, then the trigonometric function will get change.
So you have to find sin (45)
And check that cos is negative in the second quadrant, hence sin45 = 1/root2 with negative sign
So cos(135) = -1/root2
Similarly do for other.
Here you have to check whether cos is positive in the second quadrant or not, and when you use 90 degrees, then the trigonometric function will get change.
So you have to find sin (45)
And check that cos is negative in the second quadrant, hence sin45 = 1/root2 with negative sign
So cos(135) = -1/root2
Similarly do for other.