Question
Find the value of the given trigonometric
expression: (sin 15°cos 75° + cos²15°) × sin 30° + (cos 60°tan 45°) × sec 60°Solution
(sin 15°cos 75° + cos²15°) × sin 30° + (cos 60°tan 45°) × sec 60° = {sin 15°cos (90° – 15°) + cos²15°} × sin 30° + cos 60°tan 45°sec 60° Using, cos (90° – A) = sin A = (sin²15° + cos²15°) sin 30° + cos 60°tan45°sec 60° Using, sin²A + cos²A = 1 = {1 × (1/2)} + {(1/2) × 1 × 2} = (1/2) + 1 = (3/2)
A boat takes 7 hours to cover 259 km upstream and 9 hours to cover 477 km downstream. Find the time taken by the boat to cover 645 km upstream and 660 k...
A boat covers 24km upstream and 36km downstream in 6 hours while it covers 36km upstream and 24km downstream in 13/2 hours. The speed of the Boat is.Â
The speed of the stream is 11 km/h. Boat ‘A’ covers 84 km distance against the stream in 6 hours and boat ‘B’ covers 90 km distance against the ...
When travelling downstream, a boat takes 4.25 hours to travel 204 km. If the speed of the stream is (3/8)th of downstream speed of the boat, ...
Covering 54 km upstream and 150 km downstream takes a boat 8 hours in total. The boat’s still-water speed is 18 km/h more than the stream. What is the...
A boat can travel 36 km downstream in 40 min. The ratio of the speed of the boat in still water to the speed of the stream is 5: 4. How much time will t...
A man can row at 36 km/hr in still water. In a stream which is flowing at 12 km/hr, it takes him 3 hrs to a place and back. How far is the place?
The ratio of the speed of the boat in upstream to that of in downstream is 3:4, respectively. If the speed of the current is 5 km/h, then find the speed...
A boat can cover 60 km in still water and 75 km in downstream in 4 hours and 3 hours respectively. Find the time taken by the boat to cover 60 km upstre...
A boat’s speed against the stream is 66.67% less than its speed in still water. If it covers 180 km downstream in 4 hours, find the time (in minutes) ...