Advertisements
Advertisements
Question
If sin 3A = 1 and 0 < A < 90°, find cos 2A
Advertisements
Solution
sin 3A = 1
sin 3A = sin90°
3A = 90°
A = 30°
cos 2A = cos 2(30°)
= cos 60°
= `(1)/(2)`
APPEARS IN
RELATED QUESTIONS
If 2 sin x° − 1 = 0 and x° is an acute angle; find:
- sin x°
- x°
- cos x° and tan x°.
If 2 cos 2A = `sqrt3` and A is acute,
find:
(i) A
(ii) sin 3A
(iii) sin2 (75° - A) + cos2 (45° +A)
If 4 cos2 x = 3 and x is an acute angle;
find the value of :
(i) x
(ii) cos2 x + cot2 x
(iii) cos 3x (iv) sin 2x
Solve the following equations for A, if `sqrt3` tan A = 1
Calculate the value of A, if (tan A - 1) (cosec 3A - 1) = 0
Solve for x : cos `(x)/(3) –1` = 0
Solve for x : cos `(x/(2)+10°) = (sqrt3)/(2)`
Evaluate the following: sin22° cos44° - sin46° cos68°
Evaluate the following: `(tan42°)/(cot48°) + (cos33°)/(sin57°)`
Evaluate the following: tan(78° + θ) + cosec(42° + θ) - cot(12° - θ) - sec(48° - θ)
