tailieunhanh - SAT II Math Episode 2 Part 7

Tham khảo tài liệu 'sat ii math episode 2 part 7', ngoại ngữ, ngữ pháp tiếng anh phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Mathematics Tests 295 3. The correct answer is B . sfx 1 - 2x Square both sides X 1 - 4x 4x2 4x2 -5x l 0 4x-l x-l 0 1 X X 1 4 Checkx 4J4 1-2 4 4 V4 4 2 2 Checkx l y i 1-2 1 or 1 -1 does not check Thus x I is the only root. 4. The correct answer is D . 33 6 r 32 r 1 If the bases are equal the exponents are equal. 3 6-r 2 r-1 18-3r 2r-2 r 4 5. The correct answer is B . The first digit can be filled in 3 ways not zero . The second digit can be filled in 3 ways the third digit in 2 ways and the fourth digit in 1 remaining way. Hence the number of possible intergers is 3 3 2 1 18. 6. The correct answer is E . lira X 0O 3x2 - yfsx 4 2x2 3x -7ĨĨ 3x2 Ỉ5x 4 2 2 I 2 lim _x------ 2x2 . 3x . VI1 s 2 2 XXX 4 2 ARCO SAT II Math arco 296 Part VI 7. The correct answer is E . X2-ÓX 9 8J-16 9 16 x-3 2 y 4 2 25 radius 5 25 5 8. The correct answer is C . 2 intersections 9. The correct answer is D . Let each root r then x - r 3 x3 - 3rx2 3r2x - r3 So -3r -6 Thus r 2 10. The correct answer is B . One real root is 2. By De Moivre s Theorem the complex roots are separated by 72 . 5 Hence in the second quadrant the root is 2 cos 144 i sin 144 . 11. The correct answer is C . x2 - 3x - 10 0 x - 5 x 2 0 then x - 5 0 and x 2 0 x 5 and x - 2 Impossible or x - 5 0 and x 2 0 x 5 and x - 2 thus -2 x 5. arco ARCO SAT II Math Mathematics Tests 297 12. The correct answer is E . The length of OP is 2a 2 . The amplitude of OP is 225 or radians. Hence the polar form is 2V2J cos i sin . I 4 4 J 13. The correct answer is C . Since log10 1 0 and the log Ndecreases as it approaches zero it follows that log10 x 0. 14. The correct answer is D . The inverse of an implication is obtained by negating the hypothesis and the conclusion. Thus the inverse of the given proposition is p q. 15. 16. The correct answer is A . x y lnx2 e2O 2 5 2 In 4 e2 The correct answer is D . For f to be a function there must be a unique value of y for any given value of x. .