Trigonometric series and products

JEE Main Mathematics · Trigonometric Identities · 7 questions, latest first

• If A=(sin 3^°)/(cos 9^°)+(sin 9^°)/(cos 27^°)+(sin 27^°)/(cos 81^°) and B= tan 81^°- tan 3^°, then B/A is equal to ____.20264 April, Shift 1 · Q23
• Let a_k=( tan θ_k) i+ j and b_k= i-( cot θ_k) j, where θ_k=(2^k-1 π)/(2^n+1), for some n ∈ N, n>5. Then the value of (Σ_k=1^n|…20264 April, Shift 1 · Q24
• If sin ((π)/18) sin ((5 π)/18) sin ((7 π)/18)=K, then the value of sin ((10 K π)/3) is:20262 April, Shift 1 · Q11
• The value of (√3 cosec 20^°- sec 20^°)/(cos 20^° cos 40^° cos 60^° cos 80^°) is equal to202624 January, Shift 1 · Q14
• If Σ_r=1^13{1/(sin ((π)/4+(r-1) (π)/6) sin ((π)/4+(r π)/6))}=a √3+b, a, b ∈ Z, then a^2+b^2 is equal to:202528 January, Shift 2 · Q13
• 96 cos (π)/33 cos (2 π)/33 cos (4 π)/33 cos (8 π)/33 cos (16 π)/33 is equal to202310 April, Shift 1 · Q19
• The value of 36(4 cos^2 9^°-1)(4 cos^2 27^°-1)(4 cos^2 81^°-1)(4 cos^2 243^°-1) is20238 April, Shift 2 · Q19