Solve to find sin x , 4cos^2 + 7sin x -7 =0
4cos2 x + 7 sinx - 7 =0 we know that sin2 + cos2 = 1 so 4(1-sin2x) + 7sinx -7 = 0 if we times out the brackets -4sin2x + 7 sinx -3 =0 4sin2x -7sinx +3 =0 (4sinx-1)(sinx +2)=0 so therefore sinx =1/4 or -2 however we know sinx cannot be less than -1 so answer is only 1/4
JP
Related Maths A Level answers
All answers ▸Find the gradient of the line 4x+9y=10.
Find the value of dy/dx at the point where x = 2 on the curve with equation y = x^ 2 √(5x – 1).
Q15 from Senior Mathematical Challenge 2018: A square is inscribed in a circle of radius 1. An isosceles triangle is inscribed in the square. What is the ratio of the area of this triangle to the area of the shaded region? (Requires Diagram))
How do I differentiate a trigonometric function for something that is not just a single variable (e.g. d/dx (sin(3x))?