Advertisements
Advertisements
प्रश्न
Evaluate the following:
`(sin 20^@)/(cos 70^@)`
उत्तर
Given that `(sin 20^@)/(cos 70^@)`
Since `sin(90 - theta) = cos theta`
`=> (sin 20)/(cos 70) = (sin(90 - 70))/cos 70`
`=> sin 20/cos 70 = cos 70/cos 70`
`=> sin 20/ cos 70 = 1`
Therefore `(sin 20^@)/(cos 70^@) = 1`
APPEARS IN
संबंधित प्रश्न
Show that:
(i) `2(cos^2 45º + tan^2 60º) – 6(sin^2 45º – tan^2 30º) = 6`
(ii) `2(cos^4 60º + sin^4 30º) – (tan^2 60º + cot^2 45º) + 3 sec^2 30º = 1/4`
Evaluate the following :
`(sin 21^@)/(cos 69^@)`
If sin x = cos y, then x + y = 45° ; write true of false
If tan (A + B) = 1 and tan(A-B)`=1/sqrt3` , 0° < A + B < 90°, A > B, then find the values of A and B.
Evaluate :
`(3 sin 3"B" + 2 cos(2"B" + 5°))/(2 cos 3"B" – sin (2"B" – 10°)` ; when "B" = 20°.
If A = 30°;
show that:
cos 2A = cos4 A - sin4 A
If A = 30°;
show that:
4 cos A cos (60° - A). cos (60° + A) = cos 3A
Without using tables, find the value of the following: `(4)/(cot^2 30°) + (1)/(sin^2 60°) - cos^2 45°`
Find the value of the following:
(sin 90° + cos 60° + cos 45°) × (sin 30° + cos 0° – cos 45°)
The value of 5 sin2 90° – 2 cos2 0° is ______.
