Date | November 2013 | Marks available | 3 | Reference code | 13N.1.sl.TZ0.5 |
Level | SL only | Paper | 1 | Time zone | TZ0 |
Command term | Find | Question number | 5 | Adapted from | N/A |
Question
Let f(x)=sin(x+π4)+k. The graph of f passes through the point (π4, 6).
Find the value of k.
Find the minimum value of f(x).
Let g(x)=sinx. The graph of g is translated to the graph of f by the vector (pq).
Write down the value of p and of q.
Markscheme
METHOD 1
attempt to substitute both coordinates (in any order) into f (M1)
eg f(π4)=6, π4=sin(6+π4)+k
correct working (A1)
eg sinπ2=1, 1+k=6
k=5 A1 N2
[3 marks]
METHOD 2
recognizing shift of π4 left means maximum at 6 R1)
recognizing k is difference of maximum and amplitude (A1)
eg 6−1
k=5 A1 N2
[3 marks]
evidence of appropriate approach (M1)
eg minimum value of sinx is −1, −1+k, f′(x)=0, (5π4, 4)
minimum value is 4 A1 N2
[2 marks]
p=−π4, q=5 (accept (−π45)) A1A1 N2
[2 marks]