if `3theta=90^@` then find `costheta`

If theta be acute angle and costheta=(15)/(17) , then the value of cot(90^(@)-theta) is

If sin theta=0.7 , then costheta,0le0lt90^(@) is

If costheta=(1)/(2) ,then find the value of 4cos^(3)theta-3costheta .

Find the general value of theta from the equation costheta+cos2theta + cos3theta=0 .

Find the general value of theta from the equation costheta+cos2theta + cos3theta=0 .

If costheta=3/4 , then find the value of 9tan^2theta+9 .

Write the value of sintheta cos(90^(@)-theta)+costheta sin(90^(@)-theta).

Without using Trigonometric Tables evaluate the following :- sinthetacostheta-(sinthetacos(90^@-theta) costheta)/(sec(90^@-theta))-(costhetasin(90^@-theta)sintheta)/(cosec(90^@-theta)) .

If : sin theta= sqrt3*costheta, "then" : 2(sin theta+costheta)-1=