[" Q.19.If "A=30^(@)" then prove that: "],[[" (i) "tan2A=(2tan A)/(1-tan^(2)A)],[" (ii) "cos2A=cos^(2)A-sin^(2)A]]

If A=30^(@), prove that sin2A=2sin A cos A=(2tan A)/(1+tan^(2)A)

If A = 30^(@) , then Prove that : (i) sin 2A = 2 sin A cos A = (2 tan A)/(1 + tan^(2)A) (ii) 2 cos^(2)A - 1 = 1 - 2 sin^(2) A

If A=30^(@) , verify that (i) sin2A=(2tanA)/(1+tan^(2)A) (ii) cos2A=(1-tan^(2)A)/(1+tan^(2)A) (iii) tan2A=(2tanA)/(1-tan^(2)A)

If A=30^(@) , then prove that : cos2A=cos^(2)A-sin^(2)A " "=(1-tan^(2)A)/(1+tan^(2)A)

If A=30^(@) , then prove that : cos2A=cos^(2)A-sin^(2)A " "=(1-tan^(2)A)/(1+tan^(2)A)

If /_A=30^(@), verify each of the following (i)sin2A=(tan A)/(1+tan^(2)A)(ii)cos A=(1-tan^(2)A)/(1+tan^(2)A)

Prove that cos^2A-sin^2A = (1-tan^2A)/(1+tan^2A) .

Prove that : (1 - tan^(2) theta)/(1 + tan^(2) theta) = cos^(2) theta - sin^(2) theta

Prove that (i) sin (90^(2)-A)cos (90^(@)-A)=(tanA)/(1+tan^(2)A) (ii) (cos(90^(@)-A).cosA)/(cotA)-sin^(2)A=0

Prove that: cos 60=(1-(tan 30)^2)/(1+(tan 30)^2)