Q. 9 K5.0( 1 Vote )

# Using diffe

cos 61°, it being given that sin 60° = 0.86603 and 1° = 0.01745 radian

Let us assume that f(x) = cos x

Also, let x = 60° so that x + Δx = 61°

60° + Δx = 61°

Δx = 1° = 0.01745 radian

On differentiating f(x) with respect to x, we get We know  When x = 60°, we have  Recall that if y = f(x) and Δx is a small increment in x, then the corresponding increment in y, Δy = f(x + Δx) – f(x), is approximately given as Here, and Δx = 0.01745

Δf = (–0.86603)(0.01745)

Δf = –0.0151122

Now, we have f(61°) = f(60°) + Δf

f(61°) = cos(60°) – 0.0151122

f(61°) = 0.5 – 0.0151122

f(61°) = 0.4848878

Thus, cos 61° ≈ 0.4848878

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation view all courses RELATED QUESTIONS :

If y = sin x and RD Sharma - Volume 1

Find the percentaRD Sharma - Volume 1

A circular metal RD Sharma - Volume 1

The radius of a sRD Sharma - Volume 1

The height of a cRD Sharma - Volume 1

Find the approximMathematics - Exemplar

Find the point onMathematics - Board Papers