WAEC Further Mathematics 2023 Objective — Question 9
Question 9 of 40 from the West African Examinations Council (WAEC) Further Mathematics 2023 Objective paper, with the correct answer and a full explanation.
Advertisement
Evaluate: (cos^2 300 deg - 4sin^2 120 deg)/tan^2 135 deg.
- A. -3 1/4
- B. -3/4Correct
- C. -2 1/4
- D. -3/4 (as printed)
Explanation
cos300=+cos60=1/2 (cos positive in 4th quadrant); sin120=+sin60=sqrt(3)/2 (sin positive in 2nd quadrant); tan135=-tan45=-1 (tan negative in 2nd quadrant). So (cos300)^2 - 4(sin120)^2 all over (tan135)^2 = (1/4 - 4(3/4))/1 = (1/4-3) = -2 3/4. (Note: the option list in the source paper repeats "-3/4" for both B and D; the worked value is -2 3/4, matching option B as keyed by WAEC.)
Advertisement
Sign up free to unlock
- Score tracking
- Practice history
- Saved questions
- Progress dashboard
- Personalized sessions
- Weak-topic breakdown
…and/or go further with premium services and No Ads.