Advertisements
Advertisements
प्रश्न
Prove that: cos 510° cos 330° + sin 390° cos 120° = -1.
उत्तर
LHS = cos 510° cos 330° + sin 390° cos 120°
= cos(360° + 150°) cos(360° – 30°) + sin(360° + 30°) × cos(180° – 60°)
= cos 150° cos 30° + sin 30° (-cos 60°)
= cos(180° – 30°) cos 30° + sin 30° cos 60°
= -cos 30° cos 30° + `1/2 xx ((-1)/2)`
`= - sqrt3/2 xx sqrt3/2 - 1/2 xx 1/2`
`= - 3/4 - 1/4`
`= (- 3 - 1)/4`
= - 1
APPEARS IN
संबंधित प्रश्न
Convert the following degree measure into radian measure.
60°
Convert the following degree measure into radian measure.
240°
Determine the quadrant in which the following degree lie.
380°
Determine the quadrant in which the following degree lie.
-140°
Find the values of the following trigonometric ratio.
tan(-855°)
Prove that:
`sin theta * cos theta {sin(pi/2 - theta) * "cosec" theta + cos (pi/2 - theta) * sec theta}` = 1
Prove that `sqrt3 "cosec" 20^circ - sin 20^circ` = 4
The value of `(3 tan 10^circ - tan^3 10^circ)/(1 - 3 tan^2 10^circ)` is:
The value of cosec-1 `(2/sqrt3)` is:
tan`(pi/4 - x)` is:
