Determine the value of the specific trigonometric function a
Determine the value of the specific trigonometric function.
a) If cos x = -5/13 and P(x) is in quadrant III, find sin 2x.
b) If cot = 3/4 and is in quadrant IV, find cot 2.
Verify the identity.
c) tan 2y=2 cot y/csc2 y-2 (as a fraction, not division)
d) sin 2=2tan/1+tan2 (as a fraction, not division)
Solution
a. cos x=-5/14
here adjacent =5 and hypotenuse=-13
therefore sin x=-12/13
sin2x=2sinxcosx=2* -12/13 *-5/13= 60/13
b. cot 2x= 1/2(cot x - tan x)
cot x= 3/4 therefore tan x=4/3
cot 2x=1/2(3/4 - 4/3)=1/2(25/12)=25/24
