Solve to find sin x , 4cos^2 + 7sin x -7 =0

4cos2 x + 7 sinx - 7 =0 we know that sin+ 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
Answered by Jo P. Maths tutor

3320 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

How many roots does the equation x^2 = x + 12 have and what are they?


Via the product rule, or otherwise, differentiate 'y = xsin(x)'.


Differentiate y = (3x^3+2x+7)/x^(1/2)


Find the 12th term and the sum of the first 9 terms on the following Arithmetic Progression: a = 2 and d = 3


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences