Q. 8cos^3(20) - 8sin^3(10) - 6cos20 + 6sin10 = 2
S.E.E. Solution
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Soln: L.H.S. = 8cos 3 20 – 8sin 3 10 – 6cos20 + 6sin10 = 2(4cos 3 20 – 4sinn 3 10 – 3cos20 + 3sin10) = 2(4cos 3 20 - 3cos20 +...
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Q. Use remainder theorem to find remainder when polynomial x^6-1 is divided by x+1.
Soln:
Remainder Theorem:
Statement: “When polynomial
f(x) is divided x-a then remainder is f(a).”
Here, f(x) = x^6-1
Comparing ... Q. Prove that: sin10.sin30.sin50.sin70 = 1/16
Soln:
... Q. Prove that: 4(cos^4A+sin^4A)/(cos^4A-sin^4A)=(3+cos4A)Sec2A
... 
Prove that: cos^2(A+120)+cos^2(A-120)+cos^2(A) = 3/2
Soln:
Use formula:
cos2A = 2cos^2(A) - 1
cos2A+1= 2cos^2(A)
(1+cos2A)/2 = cos^2(A)
i.e. cos^2(A) = (1+cos2A)/2
... Q. If 2Tanα = 3Tanβ, then show that Tan(α-β) = Sin2β/(5-Cos2β)
Soln:
2tanα=3tanβ
tanα=(3/2)tanβ
L.H.S.
= tan(α-β)
= (tanα-tanβ)/(1+tanα.tanβ)
= {(3/2)tanβ-tanβ}/{1+(3/2)tanβ.tanβ}
= ... A complete solution for SEE students.
