Question

evaluate without using trignometric tables 5sin50° sec40°-3 cos59°cosec31° answer it fast​

Answer 1

Answer:

2

Explanation:

Use the images given below for better visual clarity.

5 sin50°sec40° - 3 cos59°cosec31°

=> 5 sin50°(1/cos40°) - 3 cos59°(1/sin31°)            [secФ° = 1/sinФ°, cosecФ° = 1/cosФ°]

=> 5 sin50°(1/cos{90° - 50°}) - 3 cos59°(1/sin{90° - 59°})            [sin(90° - Ф°) = cosФ°, cos(90° - Ф°) = sinФ°]

=> 5 sin50°(1/sin50°) - 3 cos59°(1/cos59°)

=> 5(1) - 3(1) => 5 - 3 => 2