Question
Let f(x)=∣∣
∣∣cosxsinxcosxcox2xsin2x2cos2xcos3xsin3x3cos3x∣∣
∣∣, then f′(π2) is equal to
∣∣cosxsinxcosxcox2xsin2x2cos2xcos3xsin3x3cos3x∣∣
∣∣, then f′(π2) is equal to
Answer: Option C
:
C
f′(x)=∣∣
∣∣−sinxsinxcosx−2sin2xsin2x2cos2x−3sin3xsin3x3cos3x∣∣
∣∣+∣∣
∣∣cosxcosxcosxcos2x2cos2x2cos2xcos3x3cos3x3cos3x∣∣
∣∣+∣∣
∣∣cosxsinx−sinxcos2xsin2x−4sin2xcos3xsin3x−9sin3x∣∣
∣∣
f′(π2)=∣∣
∣∣−11000−23−10∣∣
∣∣+0+∣∣
∣∣01−1−1000−19∣∣
∣∣=2(1−3)+0+1(9−1)=−4+8=4
Was this answer helpful ?
:
C
f′(x)=∣∣
∣∣−sinxsinxcosx−2sin2xsin2x2cos2x−3sin3xsin3x3cos3x∣∣
∣∣+∣∣
∣∣cosxcosxcosxcos2x2cos2x2cos2xcos3x3cos3x3cos3x∣∣
∣∣+∣∣
∣∣cosxsinx−sinxcos2xsin2x−4sin2xcos3xsin3x−9sin3x∣∣
∣∣
f′(π2)=∣∣
∣∣−11000−23−10∣∣
∣∣+0+∣∣
∣∣01−1−1000−19∣∣
∣∣=2(1−3)+0+1(9−1)=−4+8=4
Was this answer helpful ?
Submit Solution