Enable contrast version

# Tutor profile: Kaylin X.

Inactive
Kaylin X.
Tutor and Mentor for 5 years
Tutor Satisfaction Guarantee

## Questions

### Subject:Organic Chemistry

TutorMe
Question:

E2 is a very stereoselective reaction. What is the exact stereochemistry necessary for an E2 reaction?

Inactive
Kaylin X.

The H must be antiperiplanar to the leaving group.

### Subject:French

TutorMe
Question:

Identifiez et corrigez la faute dans la phrase suivante: Je dois prendre le bus parce que je n'ai pas un vélo.

Inactive
Kaylin X.

La phrase correcte: Je dois prendre le bus parce que je n'ai pas DE vélo. Dans une phrase négative ("je N'ai PAS), l’article indéfini (un, une ou des) est remplacé par la préposition DE. L'exception est si le verbe dans la phrase est le verbe "être". Dans ce cas-là, on peut utiliser l’article indéfini (un, une ou des) dans une phrase négative: Ce n'est pas UN vélo. ENGLISH: The correct sentence: Je dois prendre le bus parce que je n'ai pas DE vélo. In a negative sentence ("je N'ai PAS), the indefinite article (un, une or des) is replaced by the preposition DE. The exception is if the verb in the sentence is the verb "être". In that case, we can use the indefinite article (un, une or des) in a negative sentence: Ce n'est pas UN vélo.

### Subject:Pre-Calculus

TutorMe
Question:

Evaluate sin(7π/12) exactly using the identity sin(A+B) = sinAcosB + cosAsinB

Inactive
Kaylin X.

The key here is to realize this: sin(7π/12) = sin(π/4 + π/3). After realizing that, the rest of the problem isn't too hard; just plug everything into the given identity: sin(π/4 + π/3) = sin(π/4)cos(π/3) + cos(π/4)sin(π/3) = (√2/2 • 1/2) + (√2/2 • √3/2) = √2/4 + √6/4 = (√2+√6)/4. You might ask yourself: How in the world was I supposed to realize that sin(7π/12) = sin(π/4 + π/3)? The hint is given in the problem itself. Knowing that you have to use the identity sin(A+B) is the hint that you should convert sin(7π/12) into the form sin(A+B), so by splitting the fraction 7π/12 into A and B. Furthermore, knowing that you're supposed to evaluate the question exactly (without a calculator) is a hint that A and B will be recognizable, "easy to work with" fractions, which can help you split 7π/12 into π/4 and π/3.

## Contact tutor

Send a message explaining your
needs and Kaylin will reply soon.
Contact Kaylin