" If the angle "theta=-60^(@)," find the value of "cos theta.

If the angle theta=-30^(@) , find the value of cos theta .

If sec theta+tan theta=k find the value of cos theta

If tan theta=(4)/(5), find the value of (cos theta-sin theta)/(cos theta+sin theta)

If Sintheta=cos(theta-6^(@)) , find the value of theta

If tan theta = sqrt 3 (theta is acute angle) then find the value of 1 + cos theta .

If tan theta=(a)/(b) then find the value of (cos theta+sin theta)/(cos theta-sin theta)

If sin theta_(1)+sin theta_(2)+sin theta_(3), then find the value of cos theta_(1)+cos theta_(2)+cos theta_(3)

If theta is a positive acute angle such that sec theta=cos ec60o, find the value of 2cos^(2)theta-1

If theta be positive acute angle sin3 theta=cos(2theta+15) ,find the value of theta .

If sin theta = 12/13 , find the values of cos theta and tan theta . OR If cosec theta = 13/12 , then find the value of cos theta .