Advertisements
Advertisements
प्रश्न
If angles A, B, C to a ∆ABC from an increasing AP, then sin B =
विकल्प
\[\frac{1}{2}\]
\[\frac{\sqrt{3}}{2}\]
1
\[\frac{1}{\sqrt{2}}\]
उत्तर
Let the angles of a triangle Δ ABC be (a-d), (a),(a+d)espectively which constitute an A.P.As we know that sum of all the three angles of a triangle is 180°. so, (a-d)+a(a+d)=180°
So, a =60°
Therefore, ∠ B= 60°
Hence, `sin ∠B= sqrt3/2`
APPEARS IN
संबंधित प्रश्न
Without using trigonometric tables evaluate:
`(sin 65^@)/(cos 25^@) + (cos 32^@)/(sin 58^@) - sin 28^2. sec 62^@ + cosec^2 30^@`
if `tan theta = 3/4`, find the value of `(1 - cos theta)/(1 +cos theta)`
if `cot theta = 1/sqrt3` find the value of `(1 - cos^2 theta)/(2 - sin^2 theta)`
if `3 cos theta = 1`, find the value of `(6 sin^2 theta + tan^2 theta)/(4 cos theta)`
Evaluate.
sin(90° - A) cosA + cos(90° - A) sinA
Evaluate.
sin235° + sin255°
Evaluate:
14 sin 30° + 6 cos 60° – 5 tan 45°
Find the value of x, if cos (2x – 6) = cos2 30° – cos2 60°
Prove that:
`(cos(90^circ - theta)costheta)/cottheta = 1 - cos^2theta`
Evaluate:
`(sin35^circ cos55^circ + cos35^circ sin55^circ)/(cosec^2 10^circ - tan^2 80^circ)`
Use tables to find sine of 34° 42'
Use tables to find cosine of 8° 12’
Use tables to find the acute angle θ, if the value of sin θ is 0.4848
Use tables to find the acute angle θ, if the value of sin θ is 0.6525
If 0° < A < 90°; find A, if `sinA/(secA - 1) + sinA/(secA + 1) = 2`
The value of \[\frac{\cos^3 20°- \cos^3 70°}{\sin^3 70° - \sin^3 20°}\]
In the following figure the value of cos ϕ is
Prove that:
\[\frac{sin\theta \cos(90° - \theta)cos\theta}{\sin(90° - \theta)} + \frac{cos\theta \sin(90° - \theta)sin\theta}{\cos(90° - \theta)}\]
A, B and C are interior angles of a triangle ABC. Show that
sin `(("B"+"C")/2) = cos "A"/2`
The value of the expression (cos2 23° – sin2 67°) is positive.
