prove: `cos^2 ""60^@,cos^2 ""45^@,cos^2 ""30^@` are in A.P

Prove that : cos^2 30^@, cos^2 45^@, cos^2 60^@ are in A.P.

Prove that sin^2 30^@, sin^2 45^@, sin^2 60^@ are in A.P.

Prove that: (i) cos^(2)30^(@),cos^(2)45^(@),cos^(2)60^(@) are in A.P. (ii) cot^(2)30^(@),cot^(2)45^(@),cot^(2)60^(@) are in G.P.

Verify:b. 2cos^2 45^@=cos^2 60^@+cos^2 30^@

Evaluate : sin^2 60^@+ 2tan 45^@-cos^2 30^@

Prove that : cot^2 60^@+ sin^2 45^@+ sin^2 30^@+ cos^2 90^@=13/12 .

Prove that cos 60^(@)=cos^(2)30^(@)-sin^(2)30^(@) .

The value of cos^2 75^@ +cos^2 45^@ +cos^2 15^@- cos^2 30^@-cos^2 60^@ is

Find the value of cos^2 30^@-2cos^2 60^@-4sin^2 45^@+tan45^@ .

If cos^(2)30^(@)+cos^(2)45^(@)+cos^(2)60^(@)=x , then find the value of 'x'