1) cos2θ + sin2θ = 1
2) 1 + tan2θ = sec2θ
3) 1 + cot2θ = cosec2θ
4) (secθ + tanθ) (secθ - tanθ) = 1
5) (cosecθ + cotθ) (cosecθ - cotθ) = 1
6) The function f(x) = sinx is periodic and 2π is the period
7) The function f(x) = cosx is periodic and 2π is the period
8) The function f(x) = tanx is periodic and π is the period
9) cos (A+B) = cosA cosB- sinA sinB
10) sin (A+B) = sinAcosB + cosA SinB
11) cos (A-B) = cosA cosB + sinA sinB
12) sin (A-B) = sinA cosB - cosA sinB
17) sin(A+B) . sin(A-B) = sin2A - sin2B = cos2B - cos2A
18) cos(A+B) . cos(A-B) = cos2A - sin2B = cos2B - sin2A
19) sin (A+B+C) = sinA cosB cosC + cosA sinB cosC + cosA cosB sinC -sinA sinB sinC
20) cos (A+B+C) = cosA cosB cosC + cosA sinB sinC - sinA cosB sinC - sinA sinB cosC
23) f(x) = a sinx + b cosx + c R then the maximum and minimum values of
24) (i) sin 2A = 2sinA cosA
(ii) cos2A = 2cos2 A-1 = 1-2sin2A = cos2A- sin2A
27) (i) sin3A = 3sinA- 4sin3A
(ii) cos3A = 4cos3A - 3cosA
32) (i) tanA + cotA = 2cosec 2A
(ii) cotA - tanA = 2cot 2A
33) (i) 2sinA cosB = sin (A +B) + sin (A - B)
(ii) 2cosA sinB = sin (A + B) - sin (A - B)
(iii) 2 cosA cosB = cos (A + B) + cos (A - B)
(iv) 2 sinA sinB = cos (A - B) - cos (A + B)